armv8: fsl: move ccn504 code into FSL Makefile

The generic ARMv8 assembly code contains routines for setting up
a CCN interconnect, though the Freescale SoCs are the only user.
Link this code only for Freescale targets, this saves some precious
bytes in the chronically tight SPL.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

arch/arm/lib/Makefile

@@ -44,7 +44,7 @@ obj-y	+= stack.o
 ifdef CONFIG_CPU_V7M
 obj-y	+= interrupts_m.o
 else ifdef CONFIG_ARM64
-obj-y	+= ccn504.o
+obj-$(CONFIG_FSL_LAYERSCAPE) += ccn504.o
 ifneq ($(CONFIG_GICV2)$(CONFIG_GICV3),)
 obj-y	+= gic_64.o
 endif