be2net: increase the timeout value for loopback-test FW cmd

The loopback test FW cmd may need upto 15 seconds to complete on
certain PHYs. This patch also fixes the name of the completion variable
used to synchronize FW cmd completions as it not used by the flashing
cmd alone anymore.

Signed-off-by: Suresh Reddy <suresh.reddy@emulex.com>
Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>