drm/i915/scaler: Check if vblank is sufficient for scaler

drm/i915/scaler: Check if vblank is sufficient for scaler

High refresh rate panels which may have small line times
and vblank sizes, Check if vblank size is sufficient for
enabled scaler users.

--v2:
- Use hweight* family of functions for counting bits. [Jani]
- Update precision handling for hscale and vscale. [Ankit]
- Consider chroma downscaling factor during latency
calculation. [Ankit]
- Replace function name from scaler_prefill_time to
scaler_prefill_latency.

--v3:
- hscale_k and vscale_k values are already left shifted
by 16, after multiplying by 1000, those need to be right
shifted to 16. [Ankit]
- Replace YCBCR444 to YCBCR420. [Ankit]
- Divide by 1000 * 1000 in end to get correct precision. [Ankit]
- Initialise latency to 0 to avoid any garbage.

--v4:
- Elaborate commit message and add Bspec number. [Ankit]
- Improvise latency calculation. [Ankit]
- Use ceiling value for down scaling factor when less than 1
as per bspec. [Ankit]
- Correct linetime calculation. [Ankit]
- Consider cdclk prefill adjustment while prefill
computation.[Ankit]

--v5:
- Add Bspec link in commit message trailer. [Ankit]
- Correct hscale, vscale data type.
- Use intel_crtc_compute_min_cdclk. [Ankit]

--v6:
- Update FIXME comment.
- Use cdclk_state->logical.cdclk instead of
intel_crtc_compute_min_cdclk. [Ankit]

--v7:
- Handle error return from cdclk_prefill_adjustment. [Ankit]
- Avoid incorrect round off for linetime. [Ankit]
- Correct precision. [Ankit]

--v8:
- Remove redundancy calculation added from previous patch. [Ankit]

Bspec: 70151
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250120172209.188488-7-mitulkumar.ajitkumar.golani@intel.com