drm/i915/psr: Apply underrun on PSR idle workaround

drm/i915/psr: Apply underrun on PSR idle workaround

This patch is applying workaround for underrun on idle PSR HW issue
(Wa_16025596647) when PSR is getting enabled. It uses vblank enable/disable
status, DC5/6 enabled disabled and enabled pipes count information made
available.

This patch is also adding calls to dc5/dc6, vblank enable/disable and pipe
enable/disable notification functions as needed.
intel_psr_needs_block_dc_vblank is modified to get vblank enable/disable
notification on PSR capable system.

v2: use intel_dmc interface instead of directly writing dmc register

Bspec: 74151
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Link: https://lore.kernel.org/r/20250414100508.1208774-12-jouni.hogander@intel.com