imx: Move some header files from arch-mxs to imx-common

The following headers are moved to a i.MX common location:

- regs-common.h
- regs-apbh.h
- regs-bch.h
- regs-gpmi.h
- dma.h

This way this header can be re-used also by other i.MX platforms.
For example the i.MX6 which will need it for the upcoming NAND
support.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/arch/arm/include/asm/arch-mxs/regs-clkctrl-mx28.h b/arch/arm/include/asm/arch-mxs/regs-clkctrl-mx28.h
index 23e9adc..1c2c82e 100644
--- a/arch/arm/include/asm/arch-mxs/regs-clkctrl-mx28.h
+++ b/arch/arm/include/asm/arch-mxs/regs-clkctrl-mx28.h
@@ -26,7 +26,7 @@
 #ifndef __MX28_REGS_CLKCTRL_H__
 #define __MX28_REGS_CLKCTRL_H__
 
-#include <asm/arch/regs-common.h>
+#include <asm/imx-common/regs-common.h>
 
 #ifndef	__ASSEMBLY__
 struct mxs_clkctrl_regs {