There are four commands being used to query and clear RAS and MSI-X
interrupts status. They should be contained in array of special opcodes
because these commands have several descriptors, and we need to judge
return value in the first descriptor rather than the last one as other
opcodes. In addition, we shouldn't set the NEXT_FLAG of first descriptor.

This patch fixes above issues.
Signed-off-by: NWeihang Li <liweihang@hisilicon.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>