powerpc: cleanup hw_irq.h

SET_MSR_EE() is just use in this file and doesn't provide
any added value compared to mtmsr(). Drop it.

Add a wrtee() inline function to use wrtee/wrteei insn.

Replace #ifdefs by IS_ENABLED()

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a28a20514d5f6df9629c1a117b667e48c4272736.1567068137.git.christophe.leroy@c-s.fr

arch/powerpc/include/asm/hw_irq.h

@@ -226,8 +226,8 @@ static inline bool arch_irqs_disabled(void)
 #endif /* CONFIG_PPC_BOOK3S */
 
 #ifdef CONFIG_PPC_BOOK3E
-#define __hard_irq_enable()	asm volatile("wrteei 1" : : : "memory")
-#define __hard_irq_disable()	asm volatile("wrteei 0" : : : "memory")
+#define __hard_irq_enable()	wrtee(MSR_EE)
+#define __hard_irq_disable()	wrtee(0)
 #else
 #define __hard_irq_enable()	__mtmsrd(MSR_EE|MSR_RI, 1)
 #define __hard_irq_disable()	__mtmsrd(MSR_RI, 1)
@@ -280,8 +280,6 @@ extern void force_external_irq_replay(void);
 
 #else /* CONFIG_PPC64 */
 
-#define SET_MSR_EE(x)	mtmsr(x)
-
 static inline unsigned long arch_local_save_flags(void)
 {
 	return mfmsr();
@@ -289,47 +287,44 @@ static inline unsigned long arch_local_save_flags(void)
 
 static inline void arch_local_irq_restore(unsigned long flags)
 {
-#if defined(CONFIG_BOOKE)
-	asm volatile("wrtee %0" : : "r" (flags) : "memory");
-#else
-	mtmsr(flags);
-#endif
+	if (IS_ENABLED(CONFIG_BOOKE))
+		wrtee(flags);
+	else
+		mtmsr(flags);
 }
 
 static inline unsigned long arch_local_irq_save(void)
 {
 	unsigned long flags = arch_local_save_flags();
-#ifdef CONFIG_BOOKE
-	asm volatile("wrteei 0" : : : "memory");
-#elif defined(CONFIG_PPC_8xx)
-	wrtspr(SPRN_EID);
-#else
-	SET_MSR_EE(flags & ~MSR_EE);
-#endif
+
+	if (IS_ENABLED(CONFIG_BOOKE))
+		wrtee(0);
+	else if (IS_ENABLED(CONFIG_PPC_8xx))
+		wrtspr(SPRN_EID);
+	else
+		mtmsr(flags & ~MSR_EE);
+
 	return flags;
 }
 
 static inline void arch_local_irq_disable(void)
 {
-#ifdef CONFIG_BOOKE
-	asm volatile("wrteei 0" : : : "memory");
-#elif defined(CONFIG_PPC_8xx)
-	wrtspr(SPRN_EID);
-#else
-	arch_local_irq_save();
-#endif
+	if (IS_ENABLED(CONFIG_BOOKE))
+		wrtee(0);
+	else if (IS_ENABLED(CONFIG_PPC_8xx))
+		wrtspr(SPRN_EID);
+	else
+		mtmsr(mfmsr() & ~MSR_EE);
 }
 
 static inline void arch_local_irq_enable(void)
 {
-#ifdef CONFIG_BOOKE
-	asm volatile("wrteei 1" : : : "memory");
-#elif defined(CONFIG_PPC_8xx)
-	wrtspr(SPRN_EIE);
-#else
-	unsigned long msr = mfmsr();
-	SET_MSR_EE(msr | MSR_EE);
-#endif
+	if (IS_ENABLED(CONFIG_BOOKE))
+		wrtee(MSR_EE);
+	else if (IS_ENABLED(CONFIG_PPC_8xx))
+		wrtspr(SPRN_EIE);
+	else
+		mtmsr(mfmsr() | MSR_EE);
 }
 
 static inline bool arch_irqs_disabled_flags(unsigned long flags)