mainboard: Make use of ARRAY_SIZE in buildOpts.c on AGESA platforms

Found using coccinelle.

Change-Id: I406de6cfe25d3b471dbb6f98d9c62addae008de3
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/6195
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
diff --git a/src/mainboard/hp/pavilion_m6_1035dx/buildOpts.c b/src/mainboard/hp/pavilion_m6_1035dx/buildOpts.c
index df0f8fd..bfd6383 100644
--- a/src/mainboard/hp/pavilion_m6_1035dx/buildOpts.c
+++ b/src/mainboard/hp/pavilion_m6_1035dx/buildOpts.c
@@ -35,6 +35,8 @@
 
 #include "mainboard.h"
 
+#include <stdlib.h>
+
 #include <vendorcode/amd/agesa/f15tn/AGESA.h>
 
 /*  Include the files that instantiate the configuration definitions.  */
@@ -437,4 +439,4 @@
 {
   NBACCESS (MTEnd, 0,  0, 0, 0, 0),      // End of Table
 };
-UINT8 SizeOfTableTN = sizeof (AGESA_MEM_TABLE_TN) / sizeof (AGESA_MEM_TABLE_TN[0]);
+UINT8 SizeOfTableTN = ARRAY_SIZE(AGESA_MEM_TABLE_TN);