pinctrl: sprd: Move DT parsing before registering pinctrl device

It will be failed to select default or sleep state for pins hogged
by the pin controller device, since we hadn't parsed pins configuration
in device tree before registering the pin controller device. Thus
we should move the device tree parsing function before registering
the pin controller device.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>