powerpc: Remove the unneeded trigger of decrementer interrupt in decrementer_check_overflow

Previously in order to handle the edge sensitive decrementers,
we choose to set the decrementer to 1 to trigger a decrementer
interrupt when re-enabling interrupts. But with the rework of the
lazy EE, we would replay the decrementer interrupt when re-enabling
interrupts if a decrementer interrupt occurs with irq soft-disabled.
So there is no need to trigger a decrementer interrupt in this case
any more.
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/irq.c

@@ -116,8 +116,6 @@ static inline notrace int decrementer_check_overflow(void)
  	u64 now = get_tb_or_rtc();
  	u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
  
-	if (now >= *next_tb)
-		set_dec(1);
 	return now >= *next_tb;
 }