Revert "genirq: assert that irq handlers are indeed running in hardirq context"

This reverts commit 044d408409cc4e1bc75c886e27ca85c270db104c.

The commit added a warning when handle_IRQ_event() is called outside
of hard interrupt context. This breaks the generic tasklet based
interrupt resend mechanism which is used when the hardware has no way
to retrigger the interrupt. So we get a warning for a use case which
is correct and worked for years. Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/handle.c

@@ -363,8 +363,6 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 	irqreturn_t ret, retval = IRQ_NONE;
 	unsigned int status = 0;
 
-	WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
-
 	if (!(action->flags & IRQF_DISABLED))
 		local_irq_enable_in_hardirq();