qlge: add missing free_netdev() on error in qlge_probe()

Add the missing free_netdev() before return from function
qlge_probe() in the error handling case.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>