pinctrl: tegra: Get rid of parked_reg

Remove the use of parked_reg and use parked_bit for to know
whether field is supported or not.

This is fix for the patch
commit 1d18a3f0
"pinctrl: tegra: avoid parked_reg and parked_bank

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>