Removes the 'priority' parameter from the IRQ_CONFIG macro.
This parameter was not used anymore in any architecture.
The priority is handled in the IRQ_CONNECT macro.
The documentation is updated as well.
Change-Id: I24a293c5e41bd729d5e759113e0c4a8a6a61e0dd
Signed-off-by: Juan Manuel Cruz <juan.m.cruz.alcaraz@linux.intel.com>