Make loadlist empty when booting Horizon, more nxboot.c code

fusee/fusee-secondary/src/fs_utils.h

@@ -4,6 +4,7 @@
 #include "utils.h"
 #include "sdmmc.h"
 
+size_t get_file_size(const char *filename);
 size_t read_from_file(void *dst, size_t dst_size, const char *filename);
 size_t dump_to_file(const void *src, size_t src_size, const char *filename);