egl/android: support for EGL_KHR_partial_update

This patch adds support for the EGL_KHR_partial_update extension for
android platform. It passes 36/37 tests in dEQP for EGL_KHR_partial_update.
1 test not supported.

v2: add fallback for eglSetDamageRegionKHR (Tapani)

v3: The native_window_set_surface_damage call is available only from
    Android version 6.0. Reintroduce the ANDROID_VERSION guard and
    advertise extension only if version is >= 6.0. (Emil Velikov)

v4: use newly introduced ANDROID_API_LEVEL guard rather than
    ANDROID_VERSION guard to advertise the extension.The extension
    is advertised only if ANDROID_API_LEVEL >= 23 (Android 6.0 or
    greater). Add fallback function for platforms other than Android.
    Fix possible math overflow. (Emil Velikov)
    Return immediately when n_rects is 0. Place function's entrypoint
    in alphabetical order. (Eric Engestrom)

v5: Replace unnecessary calloc with malloc (Eric)
    Check for BAD_ALLOC error (Emil)
    Check for error in native_window_set_damage_region. (Emil, Tapani,
    Eric).

Signed-off-by: Harish Krupo <harish.krupo.kps@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 7175e82..020a0bc 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -1512,6 +1512,14 @@
 }
 
 static EGLBoolean
+dri2_set_damage_region(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *surf,
+                       EGLint *rects, EGLint n_rects)
+{
+   struct dri2_egl_display *dri2_dpy = dri2_egl_display(dpy);
+   return dri2_dpy->vtbl->set_damage_region(drv, dpy, surf, rects, n_rects);
+}
+
+static EGLBoolean
 dri2_post_sub_buffer(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *surf,
                      EGLint x, EGLint y, EGLint width, EGLint height)
 {
@@ -3140,6 +3148,7 @@
    dri2_drv->base.API.SwapBuffers = dri2_swap_buffers;
    dri2_drv->base.API.SwapBuffersWithDamageEXT = dri2_swap_buffers_with_damage;
    dri2_drv->base.API.SwapBuffersRegionNOK = dri2_swap_buffers_region;
+   dri2_drv->base.API.SetDamageRegion = dri2_set_damage_region;
    dri2_drv->base.API.PostSubBufferNV = dri2_post_sub_buffer;
    dri2_drv->base.API.CopyBuffers = dri2_copy_buffers,
    dri2_drv->base.API.QueryBufferAge = dri2_query_buffer_age;