drm/xe: Fix xe_mmio_rmw32 operation

drm/xe: Fix xe_mmio_rmw32 operation

xe_mmio_rmw32 was failing to invert the passed in mask, resulting in a
register update that wasn't the expected RMW operation.  Fortunately the
impact of this mistake was limited, since this function isn't heavily
used in Xe right now; this will mostly fix some GuC PM interrupt
unmasking.

v2:
 - Rename parameters as 'clr' and 'set' to clarify semantics.  (Lucas)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230421145006.10940-1-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>