net: hns3: Use enums instead of magic number in hclge_is_special_opcode

This patch does bit of a clean-up by using already defined enums for
certain values in function hclge_is_special_opcode(). Below enums from
have been used as replacements for magic values:

enum hclge_opcode_type{
	<snip>
	HCLGE_OPC_STATS_64_BIT		= 0x0030,
	HCLGE_OPC_STATS_32_BIT		= 0x0031,
	HCLGE_OPC_STATS_MAC		= 0x0032,
	<snip>
};

Signed-off-by: Huazhong Tan <tanhuazhong@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>