drm/i915: Update memory bandwidth formulae

drm/i915: Update memory bandwidth formulae

The formulae has been updated to include more variables. Make
sure the code carries the same.

Bspec: 64631, 54023

v2: Make GEN11 follow the default route and fix calculation of
    maxdebw(RK)
v3: Fix div by zero on default case
    Correct indent for fallthrough(Jani)
v4: Fix div by zero on gen11.
v5: Fix 0 max_numchannels case
v6:
    - Split gen11/gen12 algorithms
    - Fix RKL deburst value
    - Fix difference b/ween ICL and TGL algorithms
    - Protect deinterleave from being 0
    - Warn when numchannels exceeds max_numchannels
    - Fix scaling of clk_max from different units
    - s/deinterleave/channelwidth/ in calculating peakbw
    - Fix off by one for num_planes TGL+
    - Fix SAGV check
v7: Fix div by zero error on gen11
v8: Even though the algorithm for gen11 says that we need to return
    derated bw for a qgv point whose planes are less than no of active
    planes, we return 0 for deratedbw when only one plane is allowed.
    We modify the algorithm to accommodate the case where no of active
    planes are same as the min no of planes supported by a qgv point.
v9: Fix dclk scaling for dg1

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211015210041.16858-1-radhakrishna.sripada@intel.com