util/nvramtool: Make internal function static

This function is only used in this file, so it can be made static.

Change-Id: I90e673da91eb926424d1730c268860da7fa1627b
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33948
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>

util/nvramtool/accessors/layout-bin.c

@@ -89,7 +89,7 @@ void get_layout_from_cbfs_file(void)
 	process_layout();
 }
 
-int write_cmos_layout_bin(FILE *f)
+static int write_cmos_layout_bin(FILE *f)
 {
 	const cmos_entry_t *cmos_entry;
 	const cmos_enum_t *cmos_enum;