MAINTAINERS: add git URL for swiotlb

CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

MAINTAINERS

@@ -10320,6 +10320,7 @@ F:	arch/x86/boot/video*
 SWIOTLB SUBSYSTEM
 M:	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
 L:	linux-kernel@vger.kernel.org
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb.git
 S:	Supported
 F:	lib/swiotlb.c
 F:	arch/*/kernel/pci-swiotlb.c