soc: ti: qmss: fix the case when !SMP

The irq_set_affinity_hint() will always fail when !SMP and
Networking will fail on Keystone 2 devices in this case.
Hence, fix by ignoring IRQ affinity settings when !SMP.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>