cxl: Release irqs if memory allocation fails

This minor patch plugs a potential irq leak in case of a memory
allocation failure inside function the afu_allocate_irqs. Presently the
irqs allocated to the context gets leaked if allocation of either
one of context irq_bitmap or irq_names fails.

Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>