HID: multitouch: handle faulty Elo touch device

HID: multitouch: handle faulty Elo touch device

Since kernel v5.0, one single win8 touchscreen device failed.
And it turns out this is because it reports 2 InRange usage per touch.

It's a first, and I *really* wonder how this was allowed by Microsoft in
the first place. But IIRC, Breno told me this happened *after* a firmware
upgrade...

Anyway, better be safe for those crappy devices, and make sure we have
a full slot before jumping to the next.
This won't prevent all crappy devices to fail here, but at least we will
have a safeguard as long as the contact ID and the X and Y coordinates
are placed in the report after the grabage.

Fixes: 01eaac7e5713 ("HID: multitouch: remove one copy of values")
CC: stable@vger.kernel.org # v5.0+
Reported-and-tested-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>