Input: bcm5974 - recover from failed mode switch

Input: bcm5974 - recover from failed mode switch

Mode switches sent before control response are ignored. This results in
an unresponsive trackpad and "bcm5974: bad trackpad package, length: 8"
repeated in logs.

On receiving unknown 8-byte packets, assume that mode switch was ignored
and schedule an asynchronous mode reset. The reset will switch the
device to normal mode, wait, then switch back to wellspring mode.

Signed-off-by: Liam Mitchell <mitchell.liam@gmail.com>
Link: https://lore.kernel.org/linux-input/CAOQ1CL4+DP1TuLAGNsz5GdFBTHvnTg=5q=Dr2Z1OQc6RXydSYA@mail.gmail.com/
Acked-by: Henrik Rydberg <rydberg@bitmath.org>
Link: https://patch.msgid.link/20260213-bcm5974-reset-v2-1-1837851336b0@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>