drm/i915/tgl: Implement Wa_1409804808

This workaround the CS not done issue on PIPE_CONTROL.

v2:
- replaced BIT() by REG_BIT() in all GEN7_ROW_CHICKEN2() bits
- shortened the name of the new bit

BSpec: 52890
BSpec: 46218
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200227220101.321671-1-jose.souza@intel.com