[Why]

On DCN hardware, the crtc_high_irq handler makes vupdate_high_irq
handler redundant.

All the vupdate handler does is handle vblank events, and update vrr
for DCE hw (excluding VEGA, more on that later). As far as usermode is
concerned. vstartup happens close enough to vupdate on DCN that it can
be considered the "same". Handling vblank and updating vrr at vstartup
effectively replaces vupdate on DCN.

Vega is a bit special. Like DCN, the VRR registers on Vega are
double-buffered, and swapped at vupdate. But Unlike DCN, it lacks a
vstartup interrupt. This means we can't quite remove the vupdate handler
for it, since delayed user events due to vrr are sent off there.

[How]

Remove registration of vupdate interrupt handler for DCN. Disable
vupdate interrupt if asic family DCN, enable otherwise.
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>