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/superio/nuvoton/npcd378/superio.c b/src/superio/nuvoton/npcd378/superio.c
index 3645832..9889980 100644
--- a/src/superio/nuvoton/npcd378/superio.c
+++ b/src/superio/nuvoton/npcd378/superio.c
@@ -68,7 +68,7 @@
 
 		npcd378_hwm_write_start(res->base);
 
-		unsigned int fan_lvl = get_int_option("psu_fan_lvl", 3);
+		unsigned int fan_lvl = get_uint_option("psu_fan_lvl", 3);
 		if (fan_lvl > 7)
 			fan_lvl = 3;