[Why]
We only currently drop the vblank reference when the stream is
being removed from the context. We should be dropping it whenever we
disable interrupts and reaquiring it after we re-enable them.

We also never get the extra reference correctly when re-enabling
interrupts, since grabbing the reference has the following condition:

if (!crtc_state->crc_enabled && enable)
        drm_crtc_vblank_get(crtc);

This means that crc_enabled must be *false* in order to grab the extra
reference.

[How]
Always drop the ref whenever we're disabling interrupts.

Only disable CRC capture when the stream is being removed.

Always grab the ref by setting dm_new_crtc_state->crc_enabled = false
before the call to re-enable CRC capture.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: David Francis <David.Francis@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>