QE UEC: Extend number of supported UECs to 4

This patch extends the number of supported UECs to 4. Note that the
problem of QE thread resources exhaustion is resolved by setting the
correct number of QE threads according to Ethernet type (GBE or FE).

Signed-off-by: David Saada <david.saada@ecitele.com>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>