powerpc: Fix typo in comment reference to CONFIG_TRACE_IRQFLAGS

Signed-off-by: Andrew Donnellan <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/kernel/irq.c

···
 		if (WARN_ON(mfmsr() & MSR_EE))
 			__hard_irq_disable();
 	}
-#endif /* CONFIG_TRACE_IRQFLAG */
+#endif /* CONFIG_TRACE_IRQFLAGS */
 
 	set_soft_enabled(0);