Make the Juno .dts robust against potential reordering of the CPU nodes
by adding an explicit interrupt-affinity property to the PMU node. While
we're at it, fix the PMU interrupts numbers too.

Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>