net: hns3: Remove set but not used variable 'reset_level'

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

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_err.c: In function 'hclge_log_and_clear_ppp_error':
drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_err.c:821:24: warning:
 variable 'reset_level' set but not used [-Wunused-but-set-variable]
  enum hnae3_reset_type reset_level = HNAE3_NONE_RESET;

It never used since introduction in commit
01865a50

 ("net: hns3: Add enable and process hw errors of TM scheduler")

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