el3_payload: Remove CROSS_COMPILE default

Remove the default value of CROSS_COMPILE from EL3 Makefile
and use the user-defined value.

Change-Id: Icaed8aec0a82293dbefc579b89d0eef23c676f6a
Signed-off-by: Sathees Balya <sathees.balya@arm.com>
diff --git a/el3_payload/Makefile b/el3_payload/Makefile
index f6e809f..9e6fe04 100644
--- a/el3_payload/Makefile
+++ b/el3_payload/Makefile
@@ -4,7 +4,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-CROSS_COMPILE	:=	aarch64-linux-gnu-
 CC		:=	${CROSS_COMPILE}gcc
 AS		:=	${CROSS_COMPILE}as
 LD		:=	${CROSS_COMPILE}ld
diff --git a/el3_payload/README b/el3_payload/README
index fcb3ae1..5df6e0b 100644
--- a/el3_payload/README
+++ b/el3_payload/README
@@ -10,6 +10,9 @@
 Building
 --------
 
+The environment variable CROSS_COMPILE must point to the cross compiler. Refer
+to section 4 of the User Guide for the exact version this software has been tested with.
+
 $ make PLAT=juno
 or
 $ make PLAT=fvp