omap: 4430SDP: Register the card detect GPIO properly

Without this the HSMMC driver takes GPIO 0 to be the card detect gpio
and requests/configures it. This will give rise to issues when another
driver needs to use GPIO 0. On 4430SDP, the card detection is through
TWL 6030.

Signed-off-by: Silesh C V <silesh@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>