AMD hudson and yangtze boards: Let mainboard declare power button

The power button was declared by hudson's ASL as \_SB.PCI0.PWRB, and
always had the wake source declared as GPE3. This is not the correct
wake source for all boards. On some laptops declaring a wake source is
not needed, as the wake mechanism is handled by the EC.

Move the declaration of the power button to mainboard ASL files, and
scope it as \_SB.PWRB . This also makes the naming consistent with the
examples in the ACPI spec. The wake source for the PWRB of HP Pavilion
M6 1035dx is removed, as it is incorrect.

Change-Id: I9c76566025e7f200c0376673f6c6ea299afa4a5d
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/5546
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@gmail.com>
13 files changed