Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r249449:

Fix undefined behaviour in several gpio_pin_setflags() routines (under
sys/arm and sys/mips), squelching the clang 3.3 warnings about this.

Noticed by: tinderbox and many irate spectators
Submitted by: Luiz Otavio O Souza <loos.br@gmail.com>
PR: kern/177759

Merge r232250 from head:

Correct capitalization of "Hz" in user-visible text (manpages, printf(),
etc).

MFC r227701, r227847 and r227849:
Move the device_delete_all_children() function from usb_util.c
to kern/subr_bus.c. Simplify this function so that it no longer
depends on malloc() to execute. Rename device_delete_all_children()
into device_delete_children(). Identify a few other places where
it makes sense to use device_delete_children().

MFC r229086, r228483 and r228640:
Implement better support for USB controller suspend and resume.
Fix some build issues in avr32dci.c

MFC r226173, r227843, r227848 and r227908:
Use DEVMETHOD_END to mark end of device methods.
Remove superfluous device methods.
Add some missing __FBSBID() macros.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Import the initial CPU support for the MIPS RALink RT305x SoC.
This is a MIPS4KC CPU with various embedded peripherals, including
wireless and ethernet support.

This commit includes the platform, UART, ethernet MAC and GPIO support.
The interrupt-driven GPIO code is disabled for now pending GPIO changes
from the submitter.

Submitted by: Aleksandr Rybalko <ray@dlink.ua>