wimax: i2400: Fix memory leak in i2400m_op_rfkill_sw_toggle

commit 6f3ef5c25cc762687a7341c18cbea5af54461407 upstream.

In the implementation of i2400m_op_rfkill_sw_toggle() the allocated
buffer for cmd should be released before returning. The
documentation for i2400m_msg_to_dev() says when it returns the buffer
can be reused. Meaning cmd should be released in either case. Move
kfree(cmd) before return to be reached by all execution paths.

Fixes: 2507e6ab7a9a ("wimax: i2400: fix memory leak")
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>