Patch from Holger Hans Peter Freyther

As proposed in 2282 asm-arm/arch-sa1100/ide.h is not included anymore from asm-arm/ide.h. 
If arch-sa1100/ide.h is included we abort with #error.
If lart.c is compiled we kindly warn that ide needs fixing for this board.


Signed-off-by: Holger Hans Peter Freyther
Signed-off-by: Russell King