temporal_filter_apply_sse2.asm: add ':' to label
temporal_filter_apply_sse2.asm: add ':' to label

quiets nasm warning:
label alone on a line without a colon might be in error

BUG=webm:1462

Change-Id: I660407ca60e8c9a810dba9d76afb65852029a29c

ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx