pinctrl: amd: Implement pinmux functionality

Provide pinmux functionality by implementing pinmux_ops.

Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220601152900.1012813-7-Basavaraj.Natikar@amd.com


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