Lenovo H8: Always clear audio mute

Lenovo H8: Always clear audio mute

The mute bit is set by ACPI before poweroff/going to suspend.
So clear it after resume, to have working volume control
even if the ACPI doesn't clear it on resume.

OSPM should control Audio mute with ec bit 0x30:6, so it is
safe to clear this bit even if the user has audio muted.

Change-Id: I18bebe532bf21cfb61b3d294a396bf15012f9f1a
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-on: http://review.coreboot.org/162
Reviewed-by: Peter Stuge <peter@stuge.se>
Tested-by: build bot (Jenkins)