checkpatch: don't warn about new vsprintf pointer extension '%pe'

checkpatch: don't warn about new vsprintf pointer extension '%pe'

This extension was introduced in commit 57f5677e535b ("printf: add
support for printing symbolic error names").

Link: http://lkml.kernel.org/r/20191114100416.23928-1-u.kleine-koenig@pengutronix.de
To: Andy Whitcroft <apw@canonical.com>
To: Joe Perches <joe@perches.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: kernel@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
[pmladek@suse.com: Switched the ordering: eE -> Ee]
Signed-off-by: Petr Mladek <pmladek@suse.com>