[Why]
Originally we did the amdgpu_dm_handle_vrr_transition call before
interrupts were enabled. After the interrupt toggling logic was
moved around for support enabling CRTCs with no primary planes
active this was no longer being called in the case where there
wasn't a modeset.

This fixes failures in igt@kms_vrr@* with error
"Timed out: Waiting for vblank event".

[How]
Shift them back into the loop that always ran before interrupts were
enabled.

Pull out the logic that updated VRR state into the same loop since
there's no reason these need to be split.

In the case where we're going from VRR off, no planes to VRR on, some
active planes we'll still be covered for having the VRR vupdate
handler enabled - vblank will be re-enabled at this point, it will
see that VRR is active and set the vupdate interrupt on there.
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>