MAINTAINERS: Update gvt-linux.git new repo place

gvt-linux.git repo is moved for its new place under
https://github.com/intel/gvt-linux.git

Old https://github.com/01org/gvt-linux.git

 is set
only for redirect now.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>