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/ironlake/raminit.c b/src/northbridge/intel/ironlake/raminit.c
index d8e72b9..72c3028 100644
--- a/src/northbridge/intel/ironlake/raminit.c
+++ b/src/northbridge/intel/ironlake/raminit.c
@@ -3102,7 +3102,7 @@
 	mchbar_write16(0x1170, 0xb880);
 	mchbar_clrsetbits8(0x1210, ~0, 0x84);
 
-	gfxsize = get_int_option("gfx_uma_size", 0);	/* 0 for 32MB */
+	gfxsize = get_uint_option("gfx_uma_size", 0);	/* 0 for 32MB */
 
 	ggc = 0xb00 | ((gfxsize + 5) << 4);