drm/i915: Enable transition watermarks for glk

We are mistakenly skipping transition watermarks on glk. Fix
up the condition for glk, and toss in the w/a name from
the database.

v2: Reorder the ipc enabled vs. platform check to be more sensible

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20200228203552.30273-3-ville.syrjala@linux.intel.com