drm/i915: Clarify error message on failed workaround

Let's modify the "workaround lost" error message slightly to make it
more clear what the various numbers represent.  Also, the 'expected'
value needs to be &'d with wa->read so that it doesn't include the mask
bits for masked registers (those bits are write-only in the hardware and
will usually always read out as 0's).
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201231191103.854519-1-matthew.d.roper@intel.com

drivers/gpu/drm/i915/gt/intel_workarounds.c

@@ -1383,9 +1383,9 @@ static bool
 wa_verify(const struct i915_wa *wa, u32 cur, const char *name, const char *from)
 {
 	if ((cur ^ wa->set) & wa->read) {
-		DRM_ERROR("%s workaround lost on %s! (%x=%x/%x, expected %x)\n",
+		DRM_ERROR("%s workaround lost on %s! (reg[%x]=0x%x, relevant bits were 0x%x vs expected 0x%x)\n",
 			  name, from, i915_mmio_reg_offset(wa->reg),
-			  cur, cur & wa->read, wa->set);
+			  cur, cur & wa->read, wa->set & wa->read);
 
 		return false;
 	}