dt-bindings: pinctrl: intel: Update to use generic bindings

Kernel 5.5 adds generic pin mux & cfg node schema. Update pinctrl bindings
for LGM to use these newly added schemas. Also, rename filename to match
the compatible string.

Signed-off-by: Rahul Tanwar <rahul.tanwar@linux.intel.com>
Link: https://lore.kernel.org/r/20191218062024.25475-1-rahul.tanwar@linux.intel.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>