hwc: Skip dropped layers in video only composition

No need to draw dropped layers while doing video only composition
since they are lying outside updating ROI.

Change-Id: I7bef731538e39a5b16f17314ad31f0c4e7f2b618
hwc: Set DMA state at the start of composition

* Set DMA state at the start of the composition cycle
based on the following.

Set it to LINE_MODE if the number of active rotator
sessions are 0.

Set it to BLOCK_MODE if
** A yuv-layer for any display-device requires rotation
** (or) mExtOrientation is set
** (or) mBufferMirrorMode is set

* Separate out the reset helper function into more
modular ones

Change-Id: I6a22ac4379565cd1fd2d875a7a417f4ed3ee0f1e
hwc: Clear overlay and layer-rot map from caller

Clear overlay and layer-rot map from the top level caller of
composition, rather than from the place of actual intermediate
failure. This makes sure, even in cases of GPU comp failure,
overlay and layer-rot maps are cleared and eventually pipes unset.

Change-Id: Ibf1152a0e8ca66d87bcc6b87009c4b09e451099d
hwc: Do not re-program H/W, if the frame geometry has not changed

There is no need to re-program the H/W, if the frame geometry of all
active displays, has not changed. It will help to improve performance
by avoiding re-configuration of HAL and driver, if it is not needed.

Change-Id: Ie01dce33be89afc7308a8103128d27b4b9fb5c4b
hwc: Use layer dirty rect to calculate frame's updating ROI

Use layer dirty rect instead of display frame to calculate frame's ROI.

Change-Id: If5fe93da7815efdf9b44ed683a4d80b397921cf1
h/q/d: Read minimum width and height values of the panel ROI

Read minimum width and height restrictions on ROI of a panel
through sysfs node.

Change-Id: I0e4c35cdcaee06e77955725565cfbed2f0fd91e9
hwc: Don't validate dropped layers for MDP support

Ignore dropped layers while checking MDP support for layers
when trying for full MDP composition.

Change-Id: Ia11594173759e9dcc321d72ef425615281c35b7c