i2c: omap2+: change header guard to be generic

Make the header guard to be generic to stop conflicting with
omap2 i2c header file arch/arm/include/asm/arch-omap24xx/i2c.h

Cc: Steve Sakoman <steve@sakoman.com>
Cc: Heiko <hs@denx.de>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
Cc: Wolfang Denk <wd@denx.de>

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Steve Sakoman <steve@sakoman.com>

drivers/i2c/omap24xx_i2c.h

@@ -20,8 +20,8 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  * MA 02111-1307 USA
  */
-#ifndef _OMAP24XX_I2C_H_
-#define _OMAP24XX_I2C_H_
+#ifndef _OMAP2PLUS_I2C_H_
+#define _OMAP2PLUS_I2C_H_
 
 /* I2C masks */