Improved the error generating script, so that it is a little more explicit

Signed-off-by: Anton Matkin <anton.matkin@arm.com>
diff --git a/scripts/generate_errors.pl b/scripts/generate_errors.pl
index 5e4fe38..dab3a0c 100755
--- a/scripts/generate_errors.pl
+++ b/scripts/generate_errors.pl
@@ -89,7 +89,7 @@
         $description =~ s/^\s+//;
         $description =~ s/\n( *\*)? */ /g;
         $description =~ s/\.?\s+$//;
-        push @matches, [$name, $value, $description, grep(/^.*private\/[^\/]+$/, $file)];
+        push @matches, [$name, $value, $description, scalar($file =~ /^.*private\/[^\/]+$/)];
         ++$found;
     }
     if ($found) {