pinctrl: tegra: some bits move between registers

Some of the pinmux configuration bits that exist in "drive group"
registers in Tegra30..Tegra124 move to the "pinmux" registers on future
chips. Add a flag to support this.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>