drm/i915/dg2: Add Wa_14010547955

drm/i915/dg2: Add Wa_14010547955

This workaround is documented a bit strangely in the bspec; it's listed
as an A0 workaround, but the description clarifies that the workaround
is implicitly handled by the hardware and what the driver really needs
to do is program a chicken bit to reenable some internal behavior.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116174818.2128062-3-matthew.d.roper@intel.com