Input: ALPS - Add "Dolphin" touchpad support

These touchpads use a different protocol; they have been seen on Dell
N5110, Dell 17R SE, and Fujitsu A512.

The official ALPS driver identifies them by looking for an exact match
on the E7 report: 73 03 50.  Dolphin V1 returns an EC report of
73 01 xx (02 and 0d have been seen); Dolphin V2 returns an EC report of
73 02 xx (02 has been seen).

Credits: Dave Turvene for the report format; Vincent Vanackere for the
V2 init log

Signed-off-by: Dave Turvene <dturvene@dahetral.com>
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Vincent Vanackere <vincent.vanackere@gmail.com>