MAINTAINERS: add Q: entry to kselftest for patchwork project

A new patchwork project is created to track kselftest patches.  Update
the kselftest entry in the MAINTAINERS file adding 'Q:' entry:

  https://patchwork.kernel.org/project/linux-kselftest/list/

Link: http://lkml.kernel.org/r/20180515164427.12201-1-shuah@kernel.orgSigned-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -7698,6 +7698,7 @@ KERNEL SELFTEST FRAMEWORK
 M:	Shuah Khan <shuah@kernel.org>
 L:	linux-kselftest@vger.kernel.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git
+Q:	https://patchwork.kernel.org/project/linux-kselftest/list/
 S:	Maintained
 F:	tools/testing/selftests/
 F:	Documentation/dev-tools/kselftest*