ARM: tegra: Fix Tegra PWM parent clock

ARM: tegra: Fix Tegra PWM parent clock

Default parent clock for the PWM on Tegra is a 32kHz clock and
is unable to support the requested PWM period.

Fix PWM support on Tegra20, Tegra30, Tegra114, Tegra124 and Tegra210 by
updating the parent clock for the PWM to be the PLL_P.

This commit is equivalent to Linux kernel commit:
https://lore.kernel.org/all/20221010100046.6477-1-jonathanh@nvidia.com/

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # ASUS TF T30
Tested-by: Robert Eckelmann <longnoserob@gmail.com> # ASUS TF101 T20
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # ASUS TF201 T30
Tested-by: Thierry Reding <treding@nvidia.com> # T30 and T124
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Tom <twarren@nvidia.com>