um: Remove misleading #define ARCh_IRQ_ENABLED

Due to the typo in the name, this can never be used, but
it's also misleading because our value for enabled/disabled
is always just 0/1, not an actual signal mask.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/include/asm/irqflags.h

@@ -32,7 +32,6 @@ static inline void arch_local_irq_disable(void)
 }
 
 #define ARCH_IRQ_DISABLED	0
-#define ARCh_IRQ_ENABLED	(SIGIO|SIGVTALRM)
 
 #include <asm-generic/irqflags.h>