gpio: tegra: Fix checkpatch warnings

Fix a couple of checkpatch warnings, such as complaints about bare
unsigned being used (instead of unsigned int) and missing blank lines
after declarations.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>