Add macro to calculate number of elements in an array

This patch defines the ARRAY_SIZE macro for calculating number of elements
in an array and uses it where appropriate.

Change-Id: I72746a9229f0b259323972b498b9a3999731bc9b
diff --git a/plat/fvp/aarch64/fvp_common.c b/plat/fvp/aarch64/fvp_common.c
index fcda2a8..ddaacba 100644
--- a/plat/fvp/aarch64/fvp_common.c
+++ b/plat/fvp/aarch64/fvp_common.c
@@ -115,7 +115,7 @@
 };
 #endif
 
-CASSERT((sizeof(fvp_mmap)/sizeof(fvp_mmap[0])) + FVP_BL_REGIONS \
+CASSERT(ARRAY_SIZE(fvp_mmap) + FVP_BL_REGIONS \
 		<= MAX_MMAP_REGIONS, assert_max_mmap_regions);
 
 /* Array of secure interrupts to be configured by the gic driver */
@@ -132,9 +132,6 @@
 	IRQ_SEC_SGI_7
 };
 
-const unsigned int num_sec_irqs = sizeof(irq_sec_array) /
-	sizeof(irq_sec_array[0]);
-
 /*******************************************************************************
  * Macro generating the code for the function setting up the pagetables as per
  * the platform memory map & initialize the mmu, for the given exception level
@@ -326,7 +323,7 @@
 		plat_config.gicd_base,
 		BASE_GICR_BASE,
 		irq_sec_array,
-		num_sec_irqs);
+		ARRAY_SIZE(irq_sec_array));
 }