pinctrl: tegra: use pinctrl-utils APIs for mapping

Pin control utility functions provides the function for creating
map lists.

In place of implementing APIs locally in Tegra pin control driver
for creating map lists, use the utility functions. This reduces
the code size and avoid duplication.

Changes from V1:
- Rebased change on top of V1.
- Use pinctrl_utils_dt_free_map

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