MAINTAINERS: the staging tree dropped the "-2.6" suffix

Now that we are in the 3.x days, "2.6" doesn't make sense.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

MAINTAINERS

@@ -6125,7 +6125,7 @@ S:	Maintained
 
 STAGING SUBSYSTEM
 M:	Greg Kroah-Hartman <gregkh@suse.de>
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
 L:	devel@driverdev.osuosl.org
 S:	Maintained
 F:	drivers/staging/