[zircon][syscalls] Make zx_time_t and zx_duration_t signed types

This change is part of a hard transition and breaks the layers above.

zx_time_t and zx_duration_t are now int64_t. ZX_TIME_INFINITE is now
INT64_MAX.

A negative time value passed to a syscall is treated as any other time
value that's "in the past".

Test: CQ; new unit tests; built and ran topaz system on Eve

ZX-2100 #comment

Change-Id: I2a020cb2cf3dd7212608e24c1ee90cec58dd51ef

[zircon][kernel] Use proper time types and overflow-safe arithmetic

This change is preparation for converting zx_time_t and zx_duration_t
from unsigned to signed types (ZX-2100).

1. Fix several places where the wrong time type was used (e.g.
zx_time_t instead of zx_duration_t). Because these are simple typedefs
it's easy to use the wrong one. While it generally doesn't cause a
problem, using the wrong type can be misleading and lead to bugs like
passing a relative time when an absolute time is expected.

2. Update kernel/ and some other parts of zircon to use the new
overflow-safe arithmetic functions from zircon/time.h.

Performance: Ran "/pkgfs/packages/zircon_benchmarks/0/bin/app -p" on
NUC before and after this change. Differences were withing the noise,
some slightly faster, some slightly slower.

Test: CQ

ZX-2100 #comment cleanup before conversion

Change-Id: I75d074e5850ade5385decd9bbf330497bf7610e9

[clock] zx_clock_get(ZX_CLOCK_MONOTONIC) -> zx_clock_get_monotonic()

Test: no functional change

Change-Id: Iaa513c521d96b178458acc707be3646067971701

[zx] Update callers to zx::time and zx::duration types

The zx_time_t and zx_duration_t variants will be removed eventually.

Change-Id: Icc54983edc154eee2d1258160f921c3afc212ae0

[syscalls] Rename zx_time_get to zx_clock_get

This change frees up the get() method in for a zx_time_t accessor in the
zx::time class.

Change-Id: Ia4cdc7e3e558df5ba0cfeedb27a442abf4d6f305

[dev][gauss audio] Cache invalidate VMO before reading bytes

This is necessary on arm64 for the gauss audio input driver to work.

Bug: 68019773
Test: Record using audio test app
Change-Id: Iac545ef7875c3c967196d9b64c3c3c980ed53a98

Fix buffer size in audio app

According to audio.md:
"Clients must use the returned VMOs size (in bytes) to determine the actual
size of the ring buffer..."

The audio app uses the requested buffer size for some calculation after
getting the VMO. It should use the VMO size instead.

Bug: None
Test: With gauss driver
Change-Id: Id5f6d56678a8f3be14b67036c23a2e16fdf62e0e

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[zircon][mxtl->fbl] Rename mxtl to fbl

Change-Id: Ie21b6498e1bfb0a7fa0315e40b9e5c3ee78646be

[audio][utils] Fix a bug in the audio::utils::AudioInput

Don't use the requested ring buffer size when figuring out where the
ring wraps. Instead, pay attention to the actual size of the buffer
which the driver gives us. The driver is free to allocate a larger
buffer if needed in order to satisfy alignment and DMA requirements.

Change-Id: I0ec37ec78c3c5682047325b8163169af69f10ada

[mxtl][mxalloc] Redirect all clients of mxalloc to mxtl.

Change-Id: Ib6d88937212ab23612f59add8bd028862308ead5

[audio] Continue to phase out the old audio driver interface.

++ Duplicate the device/audio2.h protocol header file into
device/audio.h. Update all symbols to be audio* instead of
audio2*.
++ Duplicate the audio2-utils library, but have it refer to audio*
instead of audio2* everywhere.
++ Rename the audio2 test app to just audio. Make it use audio-utils
instead of audio2 utils.
++ Update the bcm-pcm audio driver to use device/audio.h and audio*
symbols.
++ Update the driver interface documentation to reflect that the name
transition from audio2 -> audio is now complete.

Change-Id: Ic1eaf301cd55072dd2ebb19b61447a37c02b6aad