omap: add missing FIQ_START definition required forarch/arm/kernel/fiq.c compilation

Several ARM platforms/machines that use FIQ define their value of FIQ_START.
Since FIQ is not implemented for OMAP yet, this definition is missing from
OMAP header files.

Put an arbitrary value for FIQ_START into plat/irqs.h for OMAP. Even if not
used by the FIQ handler for Amstrad Delta, this is required for successfull
compilation of arch/arm/plat-omap/fiq.c that provides several
usefull functions.
Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/include/plat/irqs.h

@@ -428,4 +428,8 @@ void omap3_intc_resume_idle(void);
 
 #include <mach/hardware.h>
 
+#ifdef CONFIG_FIQ
+#define FIQ_START		1024
+#endif
+
 #endif