wii: Add support for hardware AES engine and cgd(4) to the WII kernel.

Add a driver for the Nintendo Wii's AES engine. The driver registers an
AES implementation for kernel use via aes_md_init(). AES-128 requests are
accelerated by hardware and all other requests are passed through to the
default (BearSSL aes_ct) implementation.

Add cgd(4) to the Wii kernel to enable disk encryption support.

Tested performance with cgd(4) and AES-128-CBC on a USB flash drive:

hwaes: 33513984 bytes transferred in 2.245 secs (14928277 bytes/sec)
bear: 33513984 bytes transferred in 7.581 secs (4420786 bytes/sec)

Many thanks to Taylor Campbell who walked me through implementing support
for non-CBC modes.

have resetbtn pull in sysmon_power and sysmon_taskq
now this builds without any other envsys drivers present

wii: Add support for Wii DVD drive.

This adds a virtual SCSI HBA driver that is able to read DVD video discs
inserted in the Wii.

branches: 1.4.2; 1.4.4;
wii: Add External interface bus and RTC support

wii: Add GPIO, I2C, and basic A/V encoder driver.

wii: Add drivers for Broadway DSP and Audio interface.

0: [*] audio0 @ bwdsp0: Broadway DSP
playback: 16, 2ch, 48000Hz
record: unavailable
(P-) slinear_be 16/16, 2ch, { 48000 }

evbppc: Add initial support for the Nintendo Wii