RDMA/siw: Fix a memory leak in siw_init_cpulist()

RDMA/siw: Fix a memory leak in siw_init_cpulist()

The error handling code doesn't free siw_cpu_info.tx_valid_cpus[0].  The
first iteration through the loop is a no-op so this is sort of an off
by one bug.  Also Bernard pointed out that we can remove the NULL
assignment and simplify the code a bit.

Fixes: f8c4999b094d ("rdma/siw: network and RDMA core interface")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Link: https://lore.kernel.org/r/20190809140904.GB3552@mwanda
Signed-off-by: Doug Ledford <dledford@redhat.com>