checkpatch: add filename before the summary line

[Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com>]

With the patch applied the output of checkpatch.pl is as follow:
./arch/arm/mach-footbridge/ebsa285-pci.c 
total: 1 errors, 0 warnings, 48 lines checked

Adding the file name allowed me to collects stats running:
	find . -name *.c |xargs ./scripts/checkpatch.pl --file |grep -B 1 total
but I though it might me useful for other purposes to add the file name
after the list of errors and warnings and before the summary,
when the list is long I find handy to print out the filename as a reminder.
   
Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 579f50f..079c73c 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1580,6 +1580,7 @@ sub process {
 
 	print report_dump();
 	if ($summary) {
+		print "$filename \n";
 		print "total: $cnt_error errors, $cnt_warn warnings, " .
 			(($check)? "$cnt_chk checks, " : "") .
 			"$cnt_lines lines checked\n";