src: Retype option API to use unsigned integers

The CMOS option system does not support negative integers. Thus, retype
and rename the option API functions to reflect this.

Change-Id: Id3480e5cfc0ec90674def7ef0919e0b7ac5b19b3
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52672
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
diff --git a/src/northbridge/intel/gm45/igd.c b/src/northbridge/intel/gm45/igd.c
index f7bdb28..7b0b1e5 100644
--- a/src/northbridge/intel/gm45/igd.c
+++ b/src/northbridge/intel/gm45/igd.c
@@ -116,7 +116,7 @@
 		sysinfo->ggc = 0x0002;
 	else {
 		/* 4 for 32MB, default if not set in CMOS */
-		u8 gfxsize = get_int_option("gfx_uma_size", 4);
+		u8 gfxsize = get_uint_option("gfx_uma_size", 4);
 
 		/* Graphics Stolen Memory: 2MB GTT (0x0300) when VT-d disabled,
 		   2MB GTT + 2MB shadow GTT (0x0b00) else. */