drm/xe: Fix LRC workarounds

drm/xe: Fix LRC workarounds

Fix 2 issues when writing LRC workarounds by copying the same handling
done when processing other RTP entries:

For masked registers, it was not correctly setting the upper 16bits.
Differently than i915, the entry itself doesn't set the upper bits
for masked registers: this is done when applying them. Testing on ADL-P:

Before:
	[drm:xe_gt_record_default_lrcs [xe]] LRC WA rcs0 save-restore MMIOs
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x2580] = 0x00000002
	...
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x7018] = 0x00002000
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x7300] = 0x00000040
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x7304] = 0x00000200

After:
	[drm:xe_gt_record_default_lrcs [xe]] LRC WA rcs0 save-restore MMIOs
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x2580] = 0x00060002
	...
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x7018] = 0x20002000
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x7300] = 0x00400040
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x7304] = 0x02000200

All of these registers are masked registers, so writing to them without
the relevant bits in the upper 16b doesn't have any effect.

Also, this adds support to regular registers; previously it was assumed
that LRC entries would only contain masked registers. However this is
not true. 0x6604 is not a masked register, but used in workarounds for
e.g.  ADL-P. See commit 28cf243a341a ("drm/i915/gt: Fix context
workarounds with non-masked regs"). In the same test with ADL-P as
above:

Before:
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x6604] = 0xe0000000
After:
	[drm:xe_gt_record_default_lrcs [xe]] REG[0x6604] = 0xe0efef6f

As can be seen, now it will read what was in the register rather than
completely overwrite the other bits.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20230906012053.1733755-5-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>