arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled

Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.

However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.

Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org

arch/arc/kernel/process.c

@@ -114,6 +114,8 @@ void arch_cpu_idle(void)
 		"sleep %0	\n"
 		:
 		:"I"(arg)); /* can't be "r" has to be embedded const */
+
+	raw_local_irq_disable();
 }
 
 #else	/* ARC700 */
@@ -122,6 +124,7 @@ void arch_cpu_idle(void)
 {
 	/* sleep, but enable both set E1/E2 (levels of interrupts) before committing */
 	__asm__ __volatile__("sleep 0x3	\n");
+	raw_local_irq_disable();
 }
 
 #endif