Correct U-Boot upstream repository

The U-Boot source moves to https://source.denx.de/u-boot/u-boot.git
effective 2021-02-28.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/board/xilinx/microblaze-generic/MAINTAINERS b/board/xilinx/microblaze-generic/MAINTAINERS
index 9a42a8b..29ed32f 100644
--- a/board/xilinx/microblaze-generic/MAINTAINERS
+++ b/board/xilinx/microblaze-generic/MAINTAINERS
@@ -1,7 +1,7 @@
 MICROBLAZE-GENERIC BOARD
 M:	Michal Simek <monstr@monstr.eu>
 S:	Maintained
-T:	git https://gitlab.denx.de/u-boot/custodians/u-boot-microblaze.git
+T:	git https://source.denx.de/u-boot/custodians/u-boot-microblaze.git
 F:	board/xilinx/microblaze-generic/
 F:	include/configs/microblaze-generic.h
 F:	configs/microblaze-generic_defconfig