devtools: fix printing subject of checked patch

devtools: fix printing subject of checked patch

If checkpatches.sh is not run with verbose option (-v),
the patch subject is printed as headline of errors only
if there is an error reported by checkpatch.pl, not with other checks.
The headline is moved to a function which is called after each check
if there is an error and if it has not already be printed.

One more addition, in verbose mode, checkpatch.pl is now announced
as done for other checks.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Neil Horman <nhorman@tuxdriver.com>