common/memsize.c: Increase save array for supporting memory size > 4GB

In ARM 64-bits, memory size can be supported is more than 4GB,
hence increasing save array is needed to cope with testing larger memory.

Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>

common/memsize.c

@@ -26,7 +26,7 @@ DECLARE_GLOBAL_DATA_PTR;
 long get_ram_size(long *base, long maxsize)
 {
 	volatile long *addr;
-	long           save[31];
+	long           save[BITS_PER_LONG - 1];
 	long           save_base;
 	long           cnt;
 	long           val;