yabel: Use X86_* instead of the more verbose M.x86.REG_*

Makes it more similar to what realmode looks like.

Change-Id: I4407431f2d979c43dd186114d67ed11845907afe
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Reviewed-on: http://review.coreboot.org/1892
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
9 files changed