qlcnic: remove set but not used variables 'cur_rings, max_hw_rings, tx_desc_info'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c:4011:5:
 warning: variable 'max_hw_rings' set but not used [-Wunused-but-set-variable]
drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c:4013:6:
 warning: variable 'cur_rings' set but not used [-Wunused-but-set-variable]
drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c:2996:25:
 warning: variable 'tx_desc_info' set but not used [-Wunused-but-set-variable]

'cur_rings, max_hw_rings' never used since introduction in commit
34e8c406 ("qlcnic: refactor Tx/SDS ring calculation and validation in driver.")
'tx_desc_info' never used since commit
95b3890a ("qlcnic: Enhance Tx timeout debugging.")
Also 'queue_type' only can be QLCNIC_RX_QUEUE/QLCNIC_TX_QUEUE,
so make a trival cleanup on if statement.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Shahed Shaikh <shahed.shaikh@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>