vfio/iommu_type1: replace kfree with kvfree

Variables allocated by kvzalloc should not be freed by kfree.
Because they may be allocated by vmalloc.
So we replace kfree with kvfree here.

Fixes: d6a4c185 ("vfio iommu: Implementation of ioctl for dirty pages tracking")
Signed-off-by: Jiacheng Shi <billsjc@sjtu.edu.cn>
Link: https://lore.kernel.org/r/20211212091600.2560-1-billsjc@sjtu.edu.cnSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/vfio_iommu_type1.c

@@ -256,7 +256,7 @@ static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, size_t pgsize)
 
 static void vfio_dma_bitmap_free(struct vfio_dma *dma)
 {
-	kfree(dma->bitmap);
+	kvfree(dma->bitmap);
 	dma->bitmap = NULL;
 }