net: hns3: Remove error log when getting pfc stats fails

When mac supports DCB, but is in GE mode, it does not support
querying pfc stats, firmware returns error when trying to
query the pfc stats. this creates a lot of noise in the kernel
log when it prints the error log.

This patch fixes it by removing the error log, because it already
return the error to the user space, so the user should be aware of
the error.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>