Remove references to old project name from common files

The project has been renamed from "Arm Trusted Firmware (ATF)" to
"Trusted Firmware-A (TF-A)" long ago. A few references to the old
project name that still remained in various places have now been
removed.

This change doesn't affect any platform files. Any "ATF" references
inside platform files, still remain.

Change-Id: Id97895faa5b1845e851d4d50f5750de7a55bf99e
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>
diff --git a/services/spd/opteed/teesmc_opteed.h b/services/spd/opteed/teesmc_opteed.h
index ec821ba..c82b58a 100644
--- a/services/spd/opteed/teesmc_opteed.h
+++ b/services/spd/opteed/teesmc_opteed.h
@@ -17,7 +17,7 @@
  * full 64 bit values in the argument registers if invoked from Aarch64
  * mode. This violates the SMC Calling Convention, but since this
  * convention only coveres API towards Normal World it's something that
- * only concerns the OP-TEE Dispatcher in ARM Trusted Firmware and OP-TEE
+ * only concerns the OP-TEE Dispatcher in Trusted Firmware-A and OP-TEE
  * OS at Secure EL1.
  */