commit 
34d8815f9512 ("checkpatch: add --showfile to allow input via pipe
to show filenames") broke the --emacs with --file option.
Fix it.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 
                if ($showfile) {
                        $prefix = "$realfile:$realline: "
                } elsif ($emacs) {
-                       $prefix = "$filename:$linenr: ";
+                       if ($file) {
+                               $prefix = "$filename:$realline: ";
+                       } else {
+                               $prefix = "$filename:$linenr: ";
+                       }
                }
 
                if ($found_file) {