pinctrl: sunplus: Add check for kcalloc

As the potential failure of the kcalloc(),
it should be better to check it in order to
avoid the dereference of the NULL pointer.

Fixes: aa74c44b ("pinctrl: Add driver for Sunplus SP7021")
Reported-by: Hacash Robot <hacashRobot@santino.com>
Signed-off-by: William Dean <williamsukatube@gmail.com>
Link: https://lore.kernel.org/r/20220710154822.2610801-1-williamsukatube@163.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>