imx/mx3: rename clock.c and iomux.c to {clock,iomux}-imx31.c

These files are only used on imx31.  This makes the name consistent with
the imx35 files.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Valentin Longchamp <valentin.longchamp@epfl.ch>

arch/arm/mach-mx3/Makefile

@@ -5,7 +5,7 @@
 # Object file lists.
 
 obj-y				:= mm.o devices.o cpu.o
-obj-$(CONFIG_ARCH_MX31)		+= clock.o iomux.o
+obj-$(CONFIG_ARCH_MX31)		+= clock-imx31.o iomux-imx31.o
 obj-$(CONFIG_ARCH_MX35)		+= clock-imx35.o
 obj-$(CONFIG_MACH_MX31ADS)	+= mx31ads.o
 obj-$(CONFIG_MACH_MX31LILLY)	+= mx31lilly.o mx31lilly-db.o