Test the new M_VLANTAG packet flag before calling m_tag_locate().  This adds little overhead of a simple bitwise operation in case hardware VLAN acceleration is on, yet saves the more expensive function call if the acceleration is off.
Test the new M_VLANTAG packet flag before calling
m_tag_locate().  This adds little overhead of a simple
bitwise operation in case hardware VLAN acceleration
is on, yet saves the more expensive function call if
the acceleration is off.

Reviewed by:	ru, glebius
X-MFC-after:	6.0

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase