arm: at91/spl: atmel_sfr: move saic redirect to separate file

To make saic redirect code sharing with other SoCs, move the
saic redirect code from SAMA5D4 particular file,
mach-at91/armv7/sama5d4_devices.c to a separate file,
mach-at91/atmel_sfr.c

Move ATMEL_SFR_AICREDIR_KEY definition to sama5d4.h, because each
SoC has its own value.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
index 49e14e8..5b89617 100644
--- a/arch/arm/mach-at91/Makefile
+++ b/arch/arm/mach-at91/Makefile
@@ -10,7 +10,7 @@
 obj-$(CONFIG_AT91SAM9N12) += mpddrc.o spl_at91.o
 obj-$(CONFIG_AT91SAM9X5) += mpddrc.o spl_at91.o
 obj-$(CONFIG_SAMA5D3) += mpddrc.o spl_atmel.o
-obj-$(CONFIG_SAMA5D4) += mpddrc.o spl_atmel.o matrix.o
+obj-$(CONFIG_SAMA5D4) += mpddrc.o spl_atmel.o matrix.o atmel_sfr.o
 obj-y += spl.o
 endif