lib/uuid: Add UUID parsing function

Implement a simple function that parses a canonical UUID string into the
common byte representation. Inspired by acpigen_write_uuid().

Change-Id: Ia1bd883c740873699814fde6c6ddc1937a40093e
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36297
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/lib/Makefile.inc

@@ -346,3 +346,5 @@ cbfs-files-$(CONFIG_GENERIC_SPD_BIN) += spd.bin
 spd.bin-file := $(LIB_SPD_BIN)
 spd.bin-type := spd
 endif
+
+ramstage-y += uuid.c