ARM: msm: Add handle_irq handler for 8660 DT machine

Commit 041f777 (ARM: msm: convert SMP platforms to
CONFIG_MULTI_IRQ_HANDLER, 2011-09-06) forgot to add the
.handle_irq for the DT machine record. Add it so we get
interrupts instead of panics on DT enabled bootloaders.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>