intel_idle: clean up the (new) state_update_enter_method function

Now that the logic for state_update_enter_method() is in its own
function, the long if .. else if .. else if .. else if chain
can be simplified by just returning from the function
at the various places. This does not change functionality,
but it makes the logic much simpler to read or modify later.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: fenrus75

drivers/idle/intel_idle.c

@@ -1849,17 +1849,26 @@ static void state_update_enter_method(struct cpuidle_state *state, int cstate)
 		WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IBRS);
 		WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE);
 		state->enter = intel_idle_xstate;
-	} else if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) &&
+		return;
+	}
+
+	if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) &&
 			   state->flags & CPUIDLE_FLAG_IBRS) {
 		/*
 		 * IBRS mitigation requires that C-states are entered
 		 * with interrupts disabled.
 		 */
 		WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE);
 		state->enter = intel_idle_ibrs;
-	} else if (state->flags & CPUIDLE_FLAG_IRQ_ENABLE) {
+		return;
+	}
+
+	if (state->flags & CPUIDLE_FLAG_IRQ_ENABLE) {
 		state->enter = intel_idle_irq;
-	} else if (force_irq_on) {
+		return;
+	}
+
+	if (force_irq_on) {
 		pr_info("forced intel_idle_irq for state %d\n", cstate);
 		state->enter = intel_idle_irq;
 	}