ANDROID: include/linux: add low power mode and fps to notifier

Introduce low power mode so that listeners are aware when display is
going into low power mode. This requires moving notifier inside sde code
to be able to retrieve the low power state.

Add mode for fps change so that clients can be
notified whenever there is a change in fps.

Include the current vrefresh in the msm_drm_notifier data provided to
registered clients.

Include the index id in the drm_panel_notifier data
provided to registered clients.

Bug: 155453628
Co-Developed-by: Adrian Salido <salidoa@google.com>
Co-Developed-by: Steve Pfetsch <spfetsch@google.com>
Co-Developed-by: Krishna Manikandan <mkrishn@codeaurora.org>
Co-Developed-by: Samantha Tran <samtran@codeaurora.org>
Co-Developed-by: Dhaval Patel <pdhaval@codeaurora.org>
[chandanu@codeaurora.org: Squashed four different gerrits
into one change]
Change-Id: I8e29ab65991b5777c3bd64182ce989e80d2462bf
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>