bnx2x: remove unused variable 'cur_data_offset'

Fix the clang build warning:

  drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c:1862:13: error: variable 'cur_data_offset' set but not used [-Werror,-Wunused-but-set-variable]
        dma_addr_t cur_data_offset;

Signed-off-by: Bill Wendling <morbo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>