hw_parse: Fix handling of DP without branch device line

It appears that when DP is disconnected it may not report presence of DP
branching devices at all in i915_display_info debugfs.

Let's handle that gracefully.
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>

site-publishing/lib/hw_parse.rb

@@ -118,12 +118,15 @@ module I915DisplayInfo
 
 
       if is_display_port(name)
-        lines.shift while !(lines.empty? || is_dp_branch_line?(lines.first))
-        branch = lines.shift.scan(/DP branch device present: (yes|no)/)
-        if branch.flatten.first == 'yes'
-          type, dev, hw, sw = get_branch_info(lines)
-          connector_status[name]['to']  = "#{type}"       if status == 'connected'
-          connector_status[name]['via'] = "#{dev} v#{sw}" if !dev.empty?
+        lines.shift while !(lines.empty? || is_dp_branch_line?(lines.first) || is_connector_line?(lines.first))
+
+        if is_dp_branch_line?(lines.first)
+          branch = lines.shift.scan(/DP branch device present: (yes|no)/)
+          if branch.flatten.first == 'yes'
+            type, dev, hw, sw = get_branch_info(lines)
+            connector_status[name]['to']  = "#{type}"       if status == 'connected'
+            connector_status[name]['via'] = "#{dev} v#{sw}" if !dev.empty?
+          end
         end
       end