cpmac: fix the receiving of 802.1q frames
cpmac: fix the receiving of 802.1q frames

Despite what the comment above CPMAC_SKB_SIZE says, the hardware also
needs to account for the FCS length in a received frame. This patch fix
the receiving of 802.1q frames which have 4 more bytes. While at it
unhardcode the definition and use the one from if_vlan.h.

Signed-off-by: Florian Fainelli <73262ad0334ab37227b2f7a0205f51db1e606681@openwrt.org>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas