qed: Fix overriding offload_tc by protocols without APP TLV

The TC received from APP TLV is stored in offload_tc, and should not be
set by protocols which did not receive an APP TLV. Fixed the condition
when overriding the offload_tc.

Signed-off-by: Denis Bolotin <denis.bolotin@cavium.com>
Signed-off-by: Michal Kalderon <michal.kalderon@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>