Fix asserts appearing in release builds

Also fix warnings generated in release builds when assert code
is absent.

Change-Id: I45b9173d3888f9e93e98eb5b4fdc06727ba5cbf4
diff --git a/bl1/bl1_main.c b/bl1/bl1_main.c
index df92374..06ab4e5 100644
--- a/bl1/bl1_main.c
+++ b/bl1/bl1_main.c
@@ -47,7 +47,9 @@
   ******************************************************************************/
 void bl1_main(void)
 {
+#if DEBUG
 	unsigned long sctlr_el3 = read_sctlr();
+#endif
 	unsigned long bl2_base;
 	unsigned int load_type = TOP_LOAD, spsr;
 	meminfo *bl1_tzram_layout;