Specify FIP filename at build time

This patch allows to define the name of the FIP at build time by
defining the FIP_NAME variable. If FIP_NAME is not defined, default
name 'fip.bin' is used.

Documentation updated accordingly.

Change-Id: Ic41f42aac379b0c958b3dfd02863ba8ba7108710
diff --git a/Makefile b/Makefile
index 8979f7f..c82c7a2 100644
--- a/Makefile
+++ b/Makefile
@@ -63,6 +63,8 @@
 # Flag used to indicate if ASM_ASSERTION should be enabled for the build.
 # This defaults to being present in DEBUG builds only.
 ASM_ASSERTION		:=	${DEBUG}
+# Default FIP file name
+FIP_NAME		:= fip.bin
 
 # Checkpatch ignores
 CHECK_IGNORE		=	--ignore COMPLEX_MACRO
@@ -256,7 +258,7 @@
 FIPTOOLPATH		?=	tools/fip_create
 FIPTOOL			?=	${FIPTOOLPATH}/fip_create
 fiptool:		${FIPTOOL}
-fip:			${BUILD_PLAT}/fip.bin
+fip:			${BUILD_PLAT}/${FIP_NAME}
 
 locate-checkpatch:
 ifndef CHECKPATCH
@@ -485,7 +487,7 @@
 endif
 
 
-${BUILD_PLAT}/fip.bin: ${FIP_DEPS} ${FIPTOOL} check_bl30 check_bl33
+${BUILD_PLAT}/${FIP_NAME}: ${FIP_DEPS} ${FIPTOOL} check_bl30 check_bl33
 			${Q}${FIPTOOL} --dump \
 				${FIP_ARGS} \
 				$@