This tidies up the setting of the PCS register.
An assumption is made that bit 4 of this register is read-only,
which according to the ICH7 datasheet, it is.
Change-Id: Ia9b7d38a87e26236f6ebc951c169cae12b13139f
Signed-off-by: Damien Zammit <damien@zamaudio.com>
Reviewed-on: https://review.coreboot.org/13015
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins)
1533f13d43