kernel: drop apu2 reboot patch

kernel: drop apu2 reboot patch

This patch really annoys me, either it needs to go upstream or be
dropped, so it's going to be dropped here.

Checking drivers/platform/x86/pcengines-apuv2.c it also appears to be
incomplete since it mentions different dmi board names depending on bios
version.

/* APU2 w/ legacy BIOS < 4.0.8 */ is 'APU2'
/* APU2 w/ legacy BIOS >= 4.0.8 */ is 'apu2'
/* APU2 w/ mainline BIOS */ is 'PC Engines apu2'

So the patch, if applicable at all, only 'works' for legacy BIOS >=
4.0.8

My APU2 on mainline BIOS reboots fine without this patch.  So let's see
if anyone screams and when they do question why legacy bios.  If patch
DOES need to be re-introduced then it needs to go upstream first.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>