New i.MX31 SPI driver

This is an SPI driver for i.MX and MXC based SoCs from Freescale. So far
only implemented and tested on i.MX31, can with a modified register layout
and definitions be used for i.MX27, I think, MXC CPUs have similar SPI
controllers too.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 0b7a2df..bc8a104 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -26,6 +26,7 @@
 LIB	:= $(obj)libspi.a
 
 COBJS-y += mpc8xxx_spi.o
+COBJS-$(CONFIG_MXC_SPI) += mxc_spi.o
 
 COBJS	:= $(COBJS-y)
 SRCS	:= $(COBJS:.o=.c)