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/i945/early_init.c b/src/northbridge/intel/i945/early_init.c
index b9c9441..d730b2e 100644
--- a/src/northbridge/intel/i945/early_init.c
+++ b/src/northbridge/intel/i945/early_init.c
@@ -149,7 +149,7 @@
 	pci_write_config32(HOST_BRIDGE, X60BAR, DEFAULT_X60BAR | 1);
 
 	/* vram size from CMOS option */
-	gfxsize = get_int_option("gfx_uma_size", 2);	/* 2 for 8MB */
+	gfxsize = get_uint_option("gfx_uma_size", 2);	/* 2 for 8MB */
 	/* make sure no invalid setting is used */
 	if (gfxsize > 6)
 		gfxsize = 2;