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/sandybridge/early_init.c b/src/northbridge/intel/sandybridge/early_init.c
index 51b8512..7acc5af 100644
--- a/src/northbridge/intel/sandybridge/early_init.c
+++ b/src/northbridge/intel/sandybridge/early_init.c
@@ -87,7 +87,7 @@
 	printk(BIOS_DEBUG, "Initializing Graphics...\n");
 
 	/* Fall back to 32 MiB for IGD memory by setting GGC[7:3] = 1 */
-	gfxsize = get_int_option("gfx_uma_size", 0);
+	gfxsize = get_uint_option("gfx_uma_size", 0);
 
 	reg16 = pci_read_config16(HOST_BRIDGE, GGC);
 	reg16 &= ~0x00f8;