kernel-doc: warn on badly formatted short description

Make kernel-doc warn when a function/struct/union/typedef does not contain
a properly formatted short description, such as:
 * scsi_devinfo: set up the dynamic device list
or
 * scsi_devinfo -

This warning is only generated when verbose (-v) mode is used.

Also explain the -v command line option in the -h output.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/kernel-doc

@@ -218,6 +218,7 @@ sub usage {
     print "         [ -function funcname [ -function funcname ...] ]\n";
     print "         [ -nofunction funcname [ -nofunction funcname ...] ]\n";
     print "         c source file(s) > outputfile\n";
+    print "         -v : verbose output, more warnings & other info listed\n";
     exit 1;
 }
 
@@ -1881,6 +1882,13 @@ sub process_file($) {
 		} else {
 		    $declaration_purpose = "";
 		}
+
+		if (($declaration_purpose eq "") && $verbose) {
+			print STDERR "Warning(${file}:$.): missing initial short description on line:\n";
+			print STDERR $_;
+			++$warnings;
+		}
+
 		if ($identifier =~ m/^struct/) {
 		    $decl_type = 'struct';
 		} elsif ($identifier =~ m/^union/) {