ARC: Remove GENERIC_PENDING_IRQ

Nothing uses the actual functionality and the MCIP controller sets the
flags which disables the deferred affinity change. The other interrupt
controller does not support affinity setting at all.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Vineet Gupta <vgupta@kernel.org>   # arch/arc/
Link: https://lore.kernel.org/all/20241210103335.373392568@linutronix.de