common: add leading underscore to get_block_size

Add a leading underscore to the get_block_size helper since it's a
common function.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
104 files changed