Input: cyapa - add gen5 trackpad read baseline support

Add read baseline function support for gen5 trackpad device, it can be used
through sysfs baseline interface.

Signed-off-by: Dudley Du <dudl@cypress.com>
Tested-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>