checkpatch: warn about qemu/queue.h head structs that are not typedef-ed

These are just like any other struct or union, so they should have
CamelCase typedefs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

scripts/checkpatch.pl

@@ -2310,6 +2310,11 @@ sub process {
 			}
 		}
 
+		if ($line =~ /^.\s*(Q(?:S?LIST|SIMPLEQ|TAILQ)_HEAD)\s*\(\s*[^,]/ &&
+		    $line !~ /^.typedef/) {
+		    ERROR("named $1 should be typedefed separately\n" . $herecurr);
+		}
+
 # Need a space before open parenthesis after if, while etc
 		if ($line=~/\b(if|while|for|switch)\(/) {
 			ERROR("space required before the open parenthesis '('\n" . $herecurr);