drm/i915: Extract cdclk requirements checking to separate function

In Gen11+ whenever we might exceed DBuf bandwidth we might need to
recalculate CDCLK which DBuf bandwidth is scaled with.
Total Dbuf bw used might change based on particular plane needs.

Thus to calculate if cdclk needs to be changed it is not enough
anymore to check plane configuration and plane min cdclk, per DBuf
bw can be calculated only after wm/ddb calculation is done and
all required planes are added into the state. In order to keep
all min_cdclk related checks in one place let's extract it into
separate function, checking and modifying any_ms.

Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200519131117.17190-3-stanislav.lisovskiy@intel.com