package/qemu: replace old configure param with new equivalent

QEMU 6.0.0 replaces in [1] --(enable|disable)-git-update with
--with-git-submodules=(update|validate|ignore). "Disable" is now "ignore".

[1] https://lore.kernel.org/qemu-devel/20201016203857.62572-1-ddstreet@canonical.com/

Signed-off-by: Joseph Burt <caseorum@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/qemu/qemu.mk

@@ -198,7 +198,7 @@ define QEMU_CONFIGURE_CMDS
 			--disable-vhost-crypto \
 			--disable-libxml2 \
 			--disable-capstone \
-			--disable-git-update \
+			--with-git-submodules=ignore \
 			--disable-opengl \
 			--disable-vhost-user-blk-server \
 			--disable-virtiofsd \