net: irda: init spinlock after memcpy

irttp_dup() copies a tsap_cb struct, but does not initialize the
spinlock in the new structure, which confuses lockdep.

Signed-off-by: Deepak Saxena <dsaxena@mvista.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>