HID: rmi: Check for additional ACM registers appended to F11 data report

If a touchpad reports the F11 data40 register then this indicates that the touchpad reports
additional ACM (Accidental Contact Mitigation) data after the F11 data in the HID attention
report. These additional bytes shift the position of the F30 button data causing the driver
to incorrectly report button state when this functionality is present. This patch accounts
for the additional data in the report.

Fixes:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1398533

Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>