bnx2x: Remove redundant assignment to err

Variable 'err' is set to -EIO but this value is never read as it is
overwritten with a new value later on, hence it is a redundant
assignment and can be removed.

Clean up the following clang-analyzer warning:
drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c:1195:2: warning: Value
stored to 'err' is never read [clang-analyzer-deadcode.DeadStores]

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>