RDMA/iwpm: Remove set but not used variable 'msg_seq'

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

drivers/infiniband/core/iwpm_util.c: In function 'iwpm_send_hello':
drivers/infiniband/core/iwpm_util.c:811:6: warning:
 variable 'msg_seq' set but not used [-Wunused-but-set-variable]

It never used since introduction in commit b0bad9ad ("RDMA/IWPM:
Support no port mapping requirements")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/iwpm_util.c

@@ -808,7 +808,6 @@ int iwpm_send_hello(u8 nl_client, int iwpm_pid, u16 abi_version)
 {
 	struct sk_buff *skb = NULL;
 	struct nlmsghdr *nlh;
-	u32 msg_seq;
 	const char *err_str = "";
 	int ret = -EINVAL;
 
@@ -818,7 +817,6 @@ int iwpm_send_hello(u8 nl_client, int iwpm_pid, u16 abi_version)
 		goto hello_num_error;
 	}
 	nlh->nlmsg_seq = iwpm_get_nlmsg_seq();
-	msg_seq = 0;
 	err_str = "Unable to put attribute of abi_version into nlmsg";
 	ret = ibnl_put_attr(skb, nlh, sizeof(u16), &abi_version,
 			    IWPM_NLA_HELLO_ABI_VERSION);