drm/i915/gvt: export find_mmio_info

export find_mmio_info to be accessible by other gvt components

Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20201223034536.17176-1-yan.y.zhao@intel.com


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