chore(xilinx): replace ATF with TFA

Since the Arm Trusted Firmware(ATF) has been renamed to Trusted
Firmware-A (TF-A), replace all the instances of ATF from code comments,
macros, variables and functions to TF-A.

Change-Id: Iab448d96158612a3effb4e49943f8d6cb43aaad5
Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Signed-off-by: Akshay Belsare <akshay.belsare@amd.com>
diff --git a/plat/xilinx/common/pm_service/pm_api_sys.c b/plat/xilinx/common/pm_service/pm_api_sys.c
index c36a0ec..900af88 100644
--- a/plat/xilinx/common/pm_service/pm_api_sys.c
+++ b/plat/xilinx/common/pm_service/pm_api_sys.c
@@ -572,7 +572,7 @@
 	uint32_t payload[PAYLOAD_ARG_CNT];
 	uint32_t module_id;
 
-	/* Return version of API which are implemented in ATF only */
+	/* Return version of API which are implemented in TF-A only */
 	switch (api_id) {
 	case PM_GET_CALLBACK_DATA:
 	case PM_GET_TRUSTZONE_VERSION: