ARC: create cpu specific version of arch_cpu_idle()

This paves way for creating a 3rd variant needed for NPS ARC700 without
littering ifdey'ery all over the place
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/include/asm/irqflags-arcv2.h

@@ -47,9 +47,6 @@
 #define ISA_INIT_STATUS_BITS	(STATUS_IE_MASK | STATUS_AD_MASK | \
 					(ARCV2_IRQ_DEF_PRIO << 1))
 
-/* SLEEP needs default irq priority (<=) which can interrupt the doze */
-#define ISA_SLEEP_ARG		(0x10 | ARCV2_IRQ_DEF_PRIO)
-
 #ifndef __ASSEMBLY__
 
 /*

arch/arc/include/asm/irqflags-compact.h

@@ -43,8 +43,6 @@
 
 #define ISA_INIT_STATUS_BITS	STATUS_IE_MASK
 
-#define ISA_SLEEP_ARG		0x3
-
 #ifndef __ASSEMBLY__
 
 /******************************************************************

arch/arc/kernel/process.c

@@ -79,15 +79,29 @@ SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new)
 	return uval;
 }
 
+#ifdef CONFIG_ISA_ARCV2
+
 void arch_cpu_idle(void)
 {
-	/* sleep, but enable all interrupts before committing */
+	/* Re-enable interrupts <= default irq priority before commiting SLEEP */
+	const unsigned int arg = 0x10 | ARCV2_IRQ_DEF_PRIO;
+
 	__asm__ __volatile__(
 		"sleep %0	\n"
 		:
-		:"I"(ISA_SLEEP_ARG)); /* can't be "r" has to be embedded const */
+		:"I"(arg)); /* can't be "r" has to be embedded const */
+}
+
+#else
+
+void arch_cpu_idle(void)
+{
+	/* sleep, but enable both set E1/E2 (levels of interrutps) before committing */
+	__asm__ __volatile__("sleep 0x3	\n");
 }
 
+#endif
+
 asmlinkage void ret_from_fork(void);
 
 /*