MAINTAINERS: Move PWM subsystem tree to kernel.org

The PWM subsystem tree is now located on kernel.org. This will hopefully
make it more reliably accessible.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

MAINTAINERS

@@ -6684,8 +6684,7 @@ PWM SUBSYSTEM
 M:	Thierry Reding <thierry.reding@gmail.com>
 L:	linux-pwm@vger.kernel.org
 S:	Maintained
-W:	http://gitorious.org/linux-pwm
-T:	git git://gitorious.org/linux-pwm/linux-pwm.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm.git
 F:	Documentation/pwm.txt
 F:	Documentation/devicetree/bindings/pwm/
 F:	include/linux/pwm.h