serial: pic32: don't assign pic32_sport::cts_gpio twice

sport->cts_gpio is first assigned -EINVAL and few lines below using
of_get_named_gpio(). Remove the first (useless) assignment.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220503063122.20957-9-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>