omap: Don't use gpio_free to change direction to input

gpio_free() should not have the side effect of setting the line to input since this prevents the gpio command from being able to set a line as output.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Joe Hershberger <joe.hershberger@gmail.com>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>