staging: fsl-mc: Extended MC bus allocator to include IRQs

All the IRQs for DPAA2 objects in the same DPRC must use
the ICID of that DPRC, as their device Id in the GIC-ITS.
Thus, all these IRQs must share the same ITT table in the GIC.
As a result, a pool of IRQs with the same device Id must be
preallocated per DPRC (fsl-mc bus instance). So, the fsl-mc
bus object allocator is extended to also provide services
to allocate IRQs to DPAA2 devices, from their parent fsl-mc bus
IRQ pool.

Signed-off-by: J. German Rivera <German.Rivera@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>