IMX: MX31: Cleanup include files and drop nasty #ifdef in drivers

As exception among the i.MX processors, the i.MX31 has headers
without general names (mx31-regs.h, mx31.h instead of imx-regs.h and
clock.h). This requires several nasty #ifdef in the drivers to
include the correct header. The patch cleans up the driver and
renames the header files as for the other i.MX processors.

Signed-off-by: Stefano Babic <sbabic@denx.de>
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
index c5ec486..89d1973 100644
--- a/drivers/i2c/mxc_i2c.c
+++ b/drivers/i2c/mxc_i2c.c
@@ -27,13 +27,8 @@
 
 #if defined(CONFIG_HARD_I2C)
 
-#if defined(CONFIG_MX31)
-#include <asm/arch/mx31.h>
-#include <asm/arch/mx31-regs.h>
-#else
-#include <asm/arch/imx-regs.h>
 #include <asm/arch/clock.h>
-#endif
+#include <asm/arch/imx-regs.h>
 
 #define IADR	0x00
 #define IFDR	0x04