drm/i915/dp: Guarantee a minimum HBlank time

Mandate a minimum Hblank symbol cycle count between BlankingStart and
BlankingEnd in 8b/10b MST and 128b/132b mode.

v2: Affine calculation/updation of min HBlank to dp_mst (Jani)
v3: moved min_hblank from struct intel_dp to intel_crtc_state (Jani)
v4: use max/min functions, change intel_xx *intel_xx to intel_xx *xx
    (Jani)
    Limit hblank to 511 and accommodate BS/BE in calculated value
    (Srikanth)
v5: Some spelling corrections (Suraj)
v6: Removed DP2.1 in comment as this is applicable for both DP2.1 and
    DP1.4 (Suraj)
v7: crtc_state holds the logical values and the register value
    computation is moved to mst_enable() (Jani)
v8: Limit max hblank to 0x10, disable min_hblank on mst_disable (Jani)

Bspec: 74379
Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250122-hblank-v9-1-90afda006685@intel.com