bnxt_en: remove set but not used variable 'rx_stats'

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

drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c: In function 'bnxt_vf_rep_rx':
drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c:212:28: warning:
 variable 'rx_stats' set but not used [-Wunused-but-set-variable]
  struct bnxt_vf_rep_stats *rx_stats;

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>