This patch attempts to modernize core Alchemy interrupt handling code.

- add irq_chips for irq controllers instead of irq type,
- add a set_type() hook to change irq trigger type during runtime,
- add a set_wake() hook to control GPIO0..7 based wakeup,
- use linux' IRQF_TRIGGER_ constants instead of homebrew ones,
- enable GENERIC_HARDIRQS_NO__DO_IRQ.
- simplify plat_irq_dispatch
- merge au1xxx_irqmap into irq.c file, the only place where its
  contents are referenced.
- board_init_irq() is now mandatory for every board; use it to register
  the remaining (gpio-based) interrupt sources; update all boards
  accordingly.

Run-tested on Db1200 and other Au1200 based platforms.
Signed-off-by: NManuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

 delete mode 100644 arch/mips/alchemy/common/au1xxx_irqmap.c

Not every alchemy-based board might want these options forced on it,
and most of this stuff seems to be intended for devboard code anyway.
Remove commandline mangling code out of common chip code and instead
add relevant sections to all in-tree boards to not change existing
behaviour.
Signed-off-by: NManuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Share some code and merge small files:
- Extract the prom init code from all devboard files (they only differ in
  memory configuration).
- Merge the irq configuration into board setup code.
- Merge smaller files into board setup code.
Signed-off-by: NManuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

 delete mode 100644 arch/mips/alchemy/devboards/db1x00/init.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1000/init.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1000/irqmap.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1100/init.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1100/irqmap.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1200/init.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1500/init.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1500/irqmap.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1550/init.c
 delete mode 100644 arch/mips/alchemy/devboards/pb1550/irqmap.c
 create mode 100644 arch/mips/alchemy/devboards/prom.c

This should ease sharing of common devboard code.
Signed-off-by: NManuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>