UPSTREAM: drm/i915/dsb: Introduce intel_dsb_wait_vblank_delay()

Add intel_dsb_wait_vblank_delay() which instructs the DSB
to wait for duration between the undelayed and delayed vblanks.
We'll need this as the DSB can only directly wait for the
undelayed vblank, but we'll need to wait until the delayed
vblank has elapsed as well.

Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240930170415.23841-10-ville.syrjala@linux.intel.com


(cherry picked from commit 08222ca1)

Bug: 406266020
Bug: 387910155
Test: DUT booted to UI

Change-Id: I22fd9e7cc2d69e44561b0f9a5b1954d928043a30
Signed-off-by: George D Sworo <george.d.sworo@intel.corp-partner.google.com>
Signed-off-by: Ryan Neph <ryanneph@google.com>