Input: clps711x-keypad - use syscon_regmap_lookup_by_phandle

Since version 5.13, the standard syscon bindings have been added
to all clps711x DT nodes, so we can now use the more general
syscon_regmap_lookup_by_phandle function to get the syscon pointer.

Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
Link: https://lore.kernel.org/r/20220420062725.25614-1-eagle.alexander923@gmail.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>