memrange: constify memranges_is_empty()

memranges_is_empty() doesn't need to manipulate the object. Mark the
parameter as const.

Change-Id: I89f4ec404c144eac8d2900945a1ccaf5cc4f88bb
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41102

Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/memrange.h

@@ -69,7 +69,7 @@ static inline void range_entry_update_tag(struct range_entry *r,
 	r->tag = new_tag;
 }
 
-static inline bool memranges_is_empty(struct memranges *ranges)
+static inline bool memranges_is_empty(const struct memranges *ranges)
 {
 	return ranges->entries == NULL;
 }