Input: alps - add support for v7 devices

Input: alps - add support for v7 devices

Such as found on the new Toshiba Portégé Z30-A and Z40-A.

Signed-off-by: Yunkang Tang <[email protected]>
[[email protected]: Remove softbutton handling, this is done in userspace]
[[email protected]: Report INPUT_PROP_BUTTONPAD]
[[email protected]: Do not report fake PRESSURE, reporting BTN_TOUCH is
 enough]
[[email protected]: Various cleanups / refactoring]
Signed-off-by: Hans de Goede <[email protected]>
Signed-off-by: Dmitry Torokhov <[email protected]>