imx: consolidate set_chipselect_size function

Move MX5 specific set_chipselect_size function into generic i.MX part,
such that MX6 based boards are able to use this function as well.

While doing this the iomuxc gpr member needed to be consolidated between
MX5 and MX6.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/arch/arm/include/asm/arch-imx/cpu.h b/arch/arm/include/asm/arch-imx/cpu.h
index a3cc96f..254136e 100644
--- a/arch/arm/include/asm/arch-imx/cpu.h
+++ b/arch/arm/include/asm/arch-imx/cpu.h
@@ -12,3 +12,8 @@
 #define MXC_CPU_MX6Q		0x63
 #define MXC_CPU_MX6D		0x64
 #define MXC_CPU_MX6SOLO		0x65 /* dummy ID */
+
+#define CS0_128					0
+#define CS0_64M_CS1_64M				1
+#define CS0_64M_CS1_32M_CS2_32M			2
+#define CS0_32M_CS1_32M_CS2_32M_CS3_32M		3