soc/amd/stoneyridge: Simplify and fix SMBUS code

Solve issues left from Change-Id Ib88a868e654ad127be70ecc506f6b90b784f8d1b
Unify code: smbus.c to have the actual execution code, sm.c and smbus_spd.c
call functions within smbus.c.

Fix some functions that wrongly use SMBHSTCTRL as the register for the
data being transfered. The correct register is SMBHSTDAT0.

Include file smbus.h should only be used by sm.c, smbus.c and smbus_spd.c.

BUG=b:62200225

Change-Id: Ibd55560c95b6752652a4f255b04198e7a4e77d05
Signed-off-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-on: https://review.coreboot.org/21887
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Marc Jones <marc@marcjonesconsulting.com>
5 files changed