HSD #15013153007: net: stmmac: fix formatting issue on VLAN Patch

commit 20befa493666eab1f9442e82432d6195b242d4b6 from
https://github.com/altera-opensource/linux-socfpga.git



This is to fix,
1) checkpatch issue on VLAN patches.
2) Minor typing error.
3) Minor logic error.

Signed-off-by: Boon Khai Ng <boon.khai.ng@intel.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>