lenovo/x60: Fetch 16 bits when trying to parse bit 13

lenovo/x60: Fetch 16 bits when trying to parse bit 13

I'm not sure if that's the right fix here, but assuming the bit mask is
right, the inb is wrong.

Change-Id: I7e33019af088780a09be12513200bec63734bf97
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Found-by: Coverity Scan #1229556
Reviewed-on: https://review.coreboot.org/16026
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Alexander Couzens <lynxis@fe80.eu>