HID: input: fix assignment of .value

The value field is actually an array of .maxfield. We should assign the
correct number to the correct usage.

Not that we never encounter a device that requires this ATM, but better
have the proper code path.

Fixes: 2dc702c9

 ("HID: input: use the Resolution Multiplier for
       high-resolution scrolling")
Cc: stable@vger.kernel.org  # v5.0+
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>