drm/i915: Enable PPGTT command parser checks

Various commands that access memory have a bit to determine whether
the graphics address specified in the command should use the GGTT or
PPGTT for translation. These checks ensure that the bit indicates
PPGTT translation.

Most of these checks use the existing bit-checking infrastructure.
The PIPE_CONTROL and MI_FLUSH_DW commands, however, are multi-function
commands. The GGTT/PPGTT bit is only relevant for certain uses of the
command. As such, this change also extends the bit-checking code to
include a "condition" mask and offset. If the condition mask is non-zero
then the parser only performs the bit check when the bits specified by
the condition mask/offset are also non-zero.

NOTE: At this point in the series PPGTT must be enabled for the parser
to work correctly. If it's not enabled, userspace will not be setting
the PPGTT bits the way the parser requires. VLV is the only platform
where this is a problem, so at this point, we disable parsing for VLV.

v2: whitespace and trailing commas fixes, rebased

OTC-Tracker: AXIA-4631
Change-Id: I3f4c76b6734f1956ec47e698230f97d0998ff92b
Signed-off-by: Brad Volkin <bradley.d.volkin@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Drop the unecessary cast Jani spotted.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>