drm/radeon/kms/atom: make sure tables are valid (v2)

Check that atom cmd and data tables are valid
before using them.

(v2)
- fix some whitespace errors noticed by Rafał Miłecki
- check a few more cases

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 94aa6b2..56107b3 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -541,8 +541,9 @@
 		int index;
 
 		index = GetIndexIntoMasterTable(COMMAND, AdjustDisplayPll);
-		atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev,
-				      &crev);
+		if (!atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev,
+					   &crev))
+			return adjusted_clock;
 
 		memset(&args, 0, sizeof(args));
 
@@ -630,8 +631,9 @@
 	memset(&args, 0, sizeof(args));
 
 	index = GetIndexIntoMasterTable(COMMAND, SetPixelClock);
-	atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev,
-			      &crev);
+	if (!atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev,
+				   &crev))
+		return;
 
 	switch (frev) {
 	case 1:
@@ -705,8 +707,9 @@
 			   &ref_div, &post_div);
 
 	index = GetIndexIntoMasterTable(COMMAND, SetPixelClock);
-	atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev,
-			      &crev);
+	if (!atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev,
+				   &crev))
+		return;
 
 	switch (frev) {
 	case 1: