kernel: bugfix IRQ release

Interrupt resources are not properly released. Mainly two problems:

  1. on IRQ free the driver was using the IRQ number instead of the the
     component base address. So, the component IRQ handlers were never
     released

  2. on IRQ free, supposing that the first problem was not there, when
     all component's IRQ handlers were released the PCI IRQ handler (VIC
     dispatcher) should have released, but it was not. In consequence of this
     even if the driver was removed an interrupt can be handled by a
     ghost handler.

Signed-off-by: Federico Vaga <federico.vaga@cern.ch>