HID: core: save one kmemdup during .probe()

Turns out the first kmemdup is only required for the .report_fixup()
driver callback. There is no need to do two kmemdup() in a row in case
.report_fixup() is not present.

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Link: https://patch.msgid.link/20241001-hid-bpf-hid-generic-v3-2-2ef1019468df@kernel.org


Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>