trivial: pinctrl core: remove extraneous code lines

In function pinctrl_get_locked, pointer p is returned on
error, and also return on no_error.
So, we just return it with no error test.

It's pretty the same in function pinctrl_lookup_state_locked:
state is returned in every case, so we drop the error test
and just return state.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>