drm/omap: protect omap_crtc's event with event_lock spinlock
drm/omap: protect omap_crtc's event with event_lock spinlock

The vblank_cb callback and the page_flip ioctl can occur together in different
CPU contexts. vblank_cb uses takes tje drm device's event_lock spinlock when
sending the vblank event and updating omap_crtc->event and omap_crtc->od_fb.

Use the same spinlock in page_flip, to make sure the above omap_crtc parameters
are configured sequentially.

Signed-off-by: Archit Taneja <49f60fff7e48ce8acf4d32f930e8060f85030a2d@ti.com>
Signed-off-by: Tomi Valkeinen <e1ca4dbb8be1acaf20734fecd2da10ed1d46a9bb@ti.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs