Dockerfile: Update QEMU git location

Per https://www.qemu.org/contribute/ the official location of the QEMU
sources are https://gitlab.com/qemu-project/qemu.git

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/tools/docker/Dockerfile b/tools/docker/Dockerfile
index 2e72717..ffbf26f 100644
--- a/tools/docker/Dockerfile
+++ b/tools/docker/Dockerfile
@@ -173,7 +173,7 @@
 	true && \
 	rm -rf /tmp/grub
 
-RUN git clone git://git.qemu.org/qemu.git /tmp/qemu && \
+RUN git clone https://gitlab.com/qemu-project/qemu.git /tmp/qemu && \
 	cd /tmp/qemu && \
 	git submodule update --init dtc && \
 	git checkout v6.1.0 && \