Move generic ipi_mb functions to common files

ipi_mb functions can be used for other Xilinx platform.
Move it to common file from platform specific files.

Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Reviewed-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>
diff --git a/plat/xilinx/zynqmp/pm_service/pm_ipi.c b/plat/xilinx/zynqmp/pm_service/pm_ipi.c
index 88e23f0..a9f0d75 100644
--- a/plat/xilinx/zynqmp/pm_service/pm_ipi.c
+++ b/plat/xilinx/zynqmp/pm_service/pm_ipi.c
@@ -7,6 +7,8 @@
 #include <arch_helpers.h>
 #include <lib/bakery_lock.h>
 #include <lib/mmio.h>
+
+#include <ipi.h>
 #include <plat_ipi.h>
 #include <plat_private.h>
 #include <plat/common/platform.h>