Filter out status register against the interrupts' mask.

Some events are being reported via DP status register, even if
corresponding interrupts have been disabled. One instance of such event
leads to generation of VBLANK when the driver is in DRM bridge mode,
which in turn results in NULL pointer dereferencing. We should avoid
processing such events in an interrupt handler context.

This problem is less noticeable when the driver operates in DMA mode, as
in this case we have DRM CRTC object instantiated and DRM framework
simply discards unwanted VBLANKs in drm_handle_vblank().
Signed-off-by: Anatoliy Klymenko <anatoliy.klymenko@amd.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240124025402.373620-5-anatoliy.klymenko@amd.com