mxc: Define architecture identifier

Define ARCH_MXC for i.MX devices. This is useful to identify features or
behaviors common to all i.MX SoCs.

The i.MX28 is omitted because its architecture is a bit different (like imx/mxc
vs. mxs in Linux).

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Andy Fleming <afleming@gmail.com>
Cc: Kim Phillips <kim.phillips@freescale.com>

arch/arm/include/asm/arch-imx/imx-regs.h

 #ifndef _IMX_REGS_H
 #define _IMX_REGS_H
+
+#define ARCH_MXC
+
 /* ------------------------------------------------------------------------
  *  Motorola IMX system registers
  * ------------------------------------------------------------------------

arch/arm/include/asm/arch-mx25/imx-regs.h

@@ -172,6 +172,8 @@ struct aips_regs {
 
 #endif
 
+#define ARCH_MXC
+
 /* AIPS 1 */
 #define IMX_AIPS1_BASE		(0x43F00000)
 #define IMX_MAX_BASE		(0x43F04000)

arch/arm/include/asm/arch-mx27/imx-regs.h

@@ -196,6 +196,8 @@ struct fuse_bank0_regs {
 
 #endif
 
+#define ARCH_MXC
+
 #define IMX_IO_BASE		0x10000000
 
 #define IMX_AIPI1_BASE		(0x00000 + IMX_IO_BASE)

arch/arm/include/asm/arch-mx31/imx-regs.h

@@ -541,6 +541,8 @@ struct esdc_regs {
 
 #endif
 
+#define ARCH_MXC
+
 #define __REG(x)     (*((volatile u32 *)(x)))
 #define __REG16(x)   (*((volatile u16 *)(x)))
 #define __REG8(x)    (*((volatile u8 *)(x)))

arch/arm/include/asm/arch-mx35/imx-regs.h

@@ -25,6 +25,8 @@
 #ifndef __ASM_ARCH_MX35_H
 #define __ASM_ARCH_MX35_H
 
+#define ARCH_MXC
+
 /*
  * IRAM
  */

arch/arm/include/asm/arch-mx5/imx-regs.h

@@ -23,6 +23,8 @@
 #ifndef __ASM_ARCH_MX5_IMX_REGS_H__
 #define __ASM_ARCH_MX5_IMX_REGS_H__
 
+#define ARCH_MXC
+
 #if defined(CONFIG_MX51)
 #define IRAM_BASE_ADDR		0x1FFE0000	/* internal ram */
 #define IPU_SOC_BASE_ADDR	0x40000000

arch/arm/include/asm/arch-mx6/imx-regs.h

@@ -19,6 +19,8 @@
 #ifndef __ASM_ARCH_MX6_IMX_REGS_H__
 #define __ASM_ARCH_MX6_IMX_REGS_H__
 
+#define ARCH_MXC
+
 #define CONFIG_SYS_CACHELINE_SIZE	32
 
 #define ROMCP_ARB_BASE_ADDR             0x00000000