pinctrl: tegra-xusb: Return void in padctl enable/disable functions

pinctrl: tegra-xusb: Return void in padctl enable/disable functions

Make the padctl functions a bit simpler by returning void instead of
always '0'.  The callers - phy init/exit - still need to return 0, but
these are smaller function without if/branching.

Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>