option.h: Introduce {get,set}_int_option() functions

The {get,set}_option() functions are not type-safe: they take a pointer
to void, without an associated length/size. Moreover, cmos_get_option()
does not always fully initialise the destination value (it has no means
to know how large it is), which can cause issues if the caller does not
initialise the value beforehand.

The idea behind this patch series is to replace the current type-unsafe
API with a type-safe equivalent, and ultimately decouple the option API
from CMOS. This would allow using different storage mechanisms with the
same option system, maximising flexibility.

Most, if not all users of get_option() have a value to fall back to, in
case the option could not be read. Thus, get_int_option() takes a value
to fall back to, which avoids repeating the same logic on call-sites.

These new functions will be put to use in subsequent commits.

Change-Id: I6bbc51135216f34518cfd05c3dc90fb68404c1cc
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47107
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/include/option.h

@@ -26,4 +26,15 @@ static inline enum cb_err get_option(void *dest, const char *name)
 	return CB_CMOS_OTABLE_DISABLED;
 }
 
+static inline enum cb_err set_int_option(const char *name, int value)
+{
+	return set_option(name, &value);
+}
+
+static inline int get_int_option(const char *name, const int fallback)
+{
+	int value = 0;
+	return get_option(&value, name) == CB_SUCCESS ? value : fallback;
+}
+
 #endif /* _OPTION_H_ */