imx: mx5: Remove legacy iomux support

Legacy iomux support is no longer needed now that all boards have been converted
to iomux-v3.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/arch/arm/cpu/armv7/mx5/Makefile b/arch/arm/cpu/armv7/mx5/Makefile
index ecd1184..e05fae9 100644
--- a/arch/arm/cpu/armv7/mx5/Makefile
+++ b/arch/arm/cpu/armv7/mx5/Makefile
@@ -27,7 +27,7 @@
 
 LIB	= $(obj)lib$(SOC).o
 
-COBJS	= soc.o clock.o iomux.o
+COBJS	= soc.o clock.o
 SOBJS = lowlevel_init.o
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)