Add suspend_scanrate_ms power management interfaces in device's
power group, so users or applications can control the power management
strategy of trackpad device according to their requirements.
Signed-off-by: NDudley Du <dudl@cypress.com>
Tested-by: NJeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>