[dev][cpu-trace] Rename several functions for thread support

This patch consists of pure function/symbol renamings, to break
these changes out of a larger patch.

x86_ipt_cpu_mode_start -> x86_ipt_start
x86_ipt_cpu_mode_stop -> x86_ipt_stop
x86_ipt_stage_cpu_data -> x86_ipt_stage_trace_data
x86_ipt_get_cpu_data -> x86_ipt_get_trace_data
MTRACE_IPT_STAGE_CPU_DATA -> MTRACE_IPT_STAGE_TRACE_DATA
MTRACE_IPT_GET_CPU_DATA -> MTRACE_IPT_GET_TRACE_DATA
MTRACE_IPT_CPU_MODE_START -> MTRACE_IPT_START
MTRACE_IPT_CPU_MODE_STOP -> MTRACE_IPT_STOP
IOCTL_IPT_ASSIGN_BUFFER_THREAD -> IOCTL_IPT_ASSIGN_THREAD_BUFFER
IOCTL_IPT_RELEASE_BUFFER_THREAD -> IOCTL_IPT_RELEASE_THREAD_BUFFER
ioctl_ipt_assign_buffer_thread_t -> ioctl_ipt_assign_thread_buffer_t

Tested: insntrace /system/bin/insntrace --help
Change-Id: I724f2730b2c8cd65c3493bbc65f01b4402076a9d

[dev][cpu-trace] Add type zx_itrace_buffer_descriptor_t

... instead of using a uint32_t.

Tested: insntrace /system/bin/insntrace --help
Change-Id: I0e0d9de881435e10eee226597e1c29c290d4f237

[dev][cpu-trace] Ensure buffers are present before freeing

They should be, but play it safe.

Tested: insntrace insntrace --help
Change-Id: I7947dd6ce42d142dd18849580338581be54a6670

[dev][cpu-trace] Move private zircon/garnet headers to zircon-internal

Tested: Builds. Further testing in garnet.
Change-Id: I61513d56d19cea40198959118ddbae7fdc6c88e4

Revert "[dev][cpu-trace] Move private zircon/garnet headers to zircon-internal"

This reverts commit 937a00818b643d6222d873b6afd64f3382800f00.

Reason for revert: Finishing the hard transition in garnet would require bringing in an unrelated patch.

Original change's description:
> [dev][cpu-trace] Move private zircon/garnet headers to zircon-internal
>
> Tested: Builds. Further testing in garnet.
> Change-Id: Iad7692bf590978afbc15240c1710faeb525db691

TBR=dje@google.com,teisenbe@google.com

Change-Id: I69f893ff7a4f53802bf93e75fd2a2466452c9106
No-Presubmit: true
No-Tree-Checks: true
No-Try: true

[dev][cpu-trace] Move private zircon/garnet headers to zircon-internal

Tested: Builds. Further testing in garnet.
Change-Id: Iad7692bf590978afbc15240c1710faeb525db691

[dev][cpu-trace] Renamings in preparation for arm port

ipm -> cpuperf
ipt -> insntrace

Tested: Compiles. Further testing on garnet side.
Change-Id: I09990ab54379ba76fe8b51e1c8cd2f4154fdf723

[dev][cpu-trace] Naming changes to prep for ARM port

Beginnings of naming changes at the higher level to be
architecture neutral.

Tested: Build
Change-Id: Iddf32d249fe8d7eb793e590d62cad49da15c09ad

[ddk][io-buffer] Rename callsites of io_buffer_init*_with_bti

ZX-1804 #comment Move all zircon callsites to final name

Change-Id: Ie35de5654841e84653582126dc1f976664c0f49d

[dev][cpu-trace] Migrate to using BTIs with io_buffer

Change-Id: I74f6146aa8b5aa3e4e48605135705d99dbf0ed0f

[ddk][device] deprecate iotxn_queue op and device_iotxn_queue()

Most of this noise is due to various drivers that were not including
assert.h or limits.h (for PAGE_SIZE) or driver.h, instead counting on
getting them indirectly via iotxn.h via driver.h

Change-Id: Ib9d0cd56a2b81f45887e1eeb79c22b3fc44d72da

[dev][cpu-trace] Move public headers to zircon/device/cpu-trace

There will be more files describing cpu events and such,
and putting them all in zircon/device will reduce the S/N
ratio of the files there.

Change-Id: I9811fcd42ee6af68a32d80e8efd5980adece040d

[dev][cpu-trace] Renamed from intel-pt

Change-Id: I84cc2adda59e16385f1aa3165e0867ab400860ae