qlcnic: fix ethtool diagnostics test

IRQ diag test was getting executed only when both register test
and link test passed. The test should get executed if ETH_TEST_FL_OFFLINE
flag is set.

Signed-off-by: Sony Chacko <sony.chacko@qlogic.com>
Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>