iomux-v3: add IOMUX_PAD_CTRL for CONFIG_MX7D
iomux-v3: add IOMUX_PAD_CTRL for imx51
iomux-v3: add support for i.mx53 with IOMUX_PAD_CTRL

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>