hid: hid-logitech-hidpp: avoid unnecessary assignments in hidpp_connect_event

hidpp->delayed_input can't be assigned to an object that already call
input_free_device when input_register_device fails.

Fixes: c39e3d5f ("HID: logitech-hidpp: late bind the input device on wireless connection")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220812025515.19467-1-hbh25y@gmail.com