pci: imx: request gpio before use

Before use GPIO, we need to request gpio first. Free gpio after use.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Stefano Babic <ssbabic@denx.de>