arm: omap3: Manually initialize GPIO if OF_CONTROL doesn't

arm: omap3: Manually initialize GPIO if OF_CONTROL doesn't

The commong initialization code manually initializes the GPIO
even when OF_CONTROL does it, so we can reduce the code size a
bit by not doing it manually when we have device tree support.

Using the omap3_logic board (dm3730), the sizes shrunk:

Before:

   text	   data	    bss	    dec	    hex	filename
 561066	  28596	 116880	 706542	  ac7ee	u-boot
  55245	   1605	   1888	  58738	   e572	spl/u-boot-spl

After
  text	   data	    bss	    dec	    hex	filename
 560898	  28548	 116872	 706318	  ac70e	u-boot
  55121	   1557	   1888	  58566	   e4c6	spl/u-boot-spl

Signed-off-by: Adam Ford <aford173@gmail.com>