ARM: OMAP: Fix relative includes for shared i2c.h file

As discussed on linux-arm-kernel, we want to avoid
relative includes for the arch/arm/*omap* shared code:

http://www.spinics.net/lists/linux-omap/msg80520.html

To fix this for the shared i2c.h, let's re-introduce
a minimal plat/i2c.h.

Note that drivers must not use this header as it will
break build for omap2+ CONFIG_MULTIPLATFORM builds.
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap1/common.h

@@ -30,7 +30,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/i2c-omap.h>
 
-#include "../plat-omap/i2c.h"
+#include <plat/i2c.h>
 
 #if defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP850)
 void omap7xx_map_io(void);

arch/arm/mach-omap1/i2c.c

@@ -23,7 +23,7 @@
 #include <mach/mux.h>
 #include "soc.h"
 
-#include "../plat-omap/i2c.h"
+#include <plat/i2c.h>
 
 #define OMAP_I2C_SIZE		0x3f
 #define OMAP1_I2C_BASE		0xfffb3800

arch/arm/mach-omap2/i2c.h

@@ -19,7 +19,7 @@
  *
  */
 
-#include "../plat-omap/i2c.h"
+#include <plat/i2c.h>
 
 #ifndef __MACH_OMAP2_I2C_H
 #define __MACH_OMAP2_I2C_H

arch/arm/plat-omap/i2c.c

@@ -31,9 +31,9 @@
 #include <linux/err.h>
 #include <linux/clk.h>
 
-#include <mach/irqs.h>
+#include <plat/i2c.h>
 
-#include "i2c.h"
+#include <mach/irqs.h>
 
 #define OMAP_I2C_MAX_CONTROLLERS 4
 static struct omap_i2c_bus_platform_data i2c_pdata[OMAP_I2C_MAX_CONTROLLERS];