ARM: bcm2835: add interrupt-names and apply correct mapping

Add interrupt-names properties to dt and apply the correct
mapping between irq and dma channels.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>