Create separate header for ARM specific SMCCC defines

Moved SMCCC defines from plat_arm.h to new <smccc_def.h> header
and include this header in all ARM platforms.

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I4cbc69c7b9307461de87b7c7bf200dd9b810e485
diff --git a/plat/xilinx/zynqmp/include/zynqmp_def.h b/plat/xilinx/zynqmp/include/zynqmp_def.h
index 5d335d9..5e7254e 100644
--- a/plat/xilinx/zynqmp/include/zynqmp_def.h
+++ b/plat/xilinx/zynqmp/include/zynqmp_def.h
@@ -7,6 +7,7 @@
 #ifndef ZYNQMP_DEF_H
 #define ZYNQMP_DEF_H
 
+#include <plat/arm/common/smccc_def.h>
 #include <plat/common/common_def.h>
 
 #define ZYNQMP_CONSOLE_ID_cadence	1