net: bna: Remove unused variable 't'

Gcc report warning as follows:

drivers/net/ethernet/brocade/bna/bfa_ioc.c:1538:6: warning:
 variable 't' set but not used [-Wunused-but-set-variable]
 1538 |  u32 t;
      |      ^

After commit c107ba171f3d ("bna: Firmware Patch Simplification"),
't' is never used, so removing it to avoid build warning.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>