i915: Fix SDVO potentially turning off randomly

Some Poulsbo cards seem to incorrectly report
SDVO_CMD_STATUS_TARGET_NOT_SPECIFIED instead of
SDVO_CMD_STATUS_PENDING, which causes the display to be turned off.

This could also happen to i915.

Signed-off-by: Guillaume Clement <gclement@baobob.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_sdvo.c

@@ -538,7 +538,8 @@ static bool intel_sdvo_read_response(struct intel_sdvo *intel_sdvo,
 				  &status))
 		goto log_fail;
 
-	while (status == SDVO_CMD_STATUS_PENDING && --retry) {
+	while ((status == SDVO_CMD_STATUS_PENDING ||
+			status == SDVO_CMD_STATUS_TARGET_NOT_SPECIFIED) && --retry) {
 		if (retry < 10)
 			msleep(15);
 		else