As reminded in http://lkml.org/lkml/2006/12/23/26, one should use
asm/hardware.h and asm/irq.h but absent-minded devs like me tends to use
asm/arch/hardware.h and/or asm/arch/irqs.h.
This patch aims at preventing such things.

In order to make it work, I had to modify asm-arm/irq.h too so that it can
be included from assembly files.
Also, as a side effect, I had to modify some headers who were using the
asm/arch/hardware.h or asm/arch/irqs.h.
Signed-off-by: NArnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>