Fix issue where registers always seem to contain their own offset.
After writing the desired register into SIRI, the requested data is
returned in SIRD. This register is 4 bytes after SIRI, commonly 0xA4.
Tested on TGL-H (SATA SIR registers are common), genuine data is
returned.
Change-Id: I322b11d53178e5b64e353c1b4e576548592c16c3
Signed-off-by: Benjamin Doron <benjamin.doron00@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61737
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>