staging: tidspbridge: request the right irq for mmu

Requested irq for mmu is currently conflicting with a DMA irq
due to recent changes to irq header files, now the offset for the
start of the interrupt controller numbering has changed.

This should be removed during a future migration to omap-iommu,
for now it is hardcoded.

Signed-off-by: Omar Ramirez Luna <omar.ramirez@copitl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>