drm/i915/tgl: Drop Wa#1178

The TGL workaround database no longer shows Wa #1178 (or anything
similar under different workaround names/numbers) so we should be able
to drop it.  In fact Swati just discovered that applying this workaround
is the root cause of some power well enable failures we've been seeing
in CI (gitlab issue 498).

Once we stop applying this WA, TGL no longer utilizes any of the special
handling provided by icl_combo_phy_aux_power_well_ops so we can just
drop back to using the standard hsw-style power well ops instead.

v3: Drop now-unused _TGL_AUX_ANAOVRD1_C definition too.  (Lucas)

Closes: https://gitlab.freedesktop.org/drm/intel/issues/498
Fixes: deea06b4

 ("drm/i915/tgl: apply Display WA #1178 to fix type C dongles")
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Swati Sharma <swati2.sharma@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191213001511.678070-3-matthew.d.roper@intel.com