libhardware: Add dirty region field to hwc layer

This change adds dirty region field to hwc_layer_1_t structure to
pass the layer's dirty region information since the previous frame.

Change-Id: I5b107b702636c6b1f662703a29dfda4793c02809
Merge pull request #1 from CyanogenMod/cm-11.0

libhardware: Add dirty region field to hwc layer