lib/memrange: avoid shadow object declarations

Fix an error where a variable named 'free' was shadowing the
function 'free'.

src/lib/memrange.c:293:73: error: declaration of 'free' shadows a global
declaration [-Werror=shadow]

Change-Id: Ie57194b392f8f00ed4fd5c76dab27299b00ae293
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/13788
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/lib/memrange.c b/src/lib/memrange.c
index cc75e01..489b562 100644
--- a/src/lib/memrange.c
+++ b/src/lib/memrange.c
@@ -290,7 +290,7 @@
 	memranges_add_resources_filter(ranges, mask, match, tag, NULL);
 }
 
-void memranges_init_empty(struct memranges *ranges, struct range_entry *free,
+void memranges_init_empty(struct memranges *ranges, struct range_entry *to_free,
                           size_t num_free)
 {
 	size_t i;
@@ -299,7 +299,7 @@
 	ranges->free_list = NULL;
 
 	for (i = 0; i < num_free; i++)
-		range_entry_link(&ranges->free_list, &free[i]);
+		range_entry_link(&ranges->free_list, &to_free[i]);
 }
 
 void memranges_init(struct memranges *ranges,