Input: tca8418_keypad - remove double read of key event register

commit 9dd46c02532a6bed6240101ecf4bbc407f8c6adf upstream.

There is no need to tread the same register twice in a row.

Fixes: ea4348c8462a ("Input: tca8418_keypad - hide gcc-4.9 -Wmaybe-un ...")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>