Rushmore touchpads are found on Dell E6230/E6430/E6530.  They use the V3
protocol with slightly tweaked init sequences and report formats.

The E7 report is 73 03 0a, and the EC report is 88 08 1d

Credits: Emmanuel Thome reported the MT bitmap changes.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Tested-by: Dave Turvene <dturvene@dahetral.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>