drm/i915/gvt: make dma map/unmap kvmgt functions as static

Make kvmgt_dma_map/unmap_guest_page as static function.
Reviewed-by: Hang Yuan <hang.yuan@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -1676,7 +1676,7 @@ static unsigned long kvmgt_gfn_to_pfn(unsigned long handle, unsigned long gfn)
 	return pfn;
 }
 
-int kvmgt_dma_map_guest_page(unsigned long handle, unsigned long gfn,
+static int kvmgt_dma_map_guest_page(unsigned long handle, unsigned long gfn,
 		unsigned long size, dma_addr_t *dma_addr)
 {
 	struct kvmgt_guest_info *info;
@@ -1725,7 +1725,7 @@ static void __gvt_dma_release(struct kref *ref)
 	__gvt_cache_remove_entry(entry->vgpu, entry);
 }
 
-void kvmgt_dma_unmap_guest_page(unsigned long handle, dma_addr_t dma_addr)
+static void kvmgt_dma_unmap_guest_page(unsigned long handle, dma_addr_t dma_addr)
 {
 	struct kvmgt_guest_info *info;
 	struct gvt_dma *entry;