net/smc: remove unused input parameters in smcr_new_buf_create

The input parameter "is_rmb" of the smcr_new_buf_create function
has never been used, remove it.

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>