Revert "ARC: [nsimosci] Add workaround for inaccuracy host timers with nSIM"

This reverts commit 05ee2ab.

No longer needed after nSIM fixes

Author: vineetgarc

arch/arc/Kconfig

@@ -410,15 +410,6 @@ config ARC_DBG_TLB_MISS_COUNT
 	  Counts number of I and D TLB Misses and exports them via Debugfs
 	  The counters can be cleared via Debugfs as well
 
-config ARC_DISABLE_SLEEP_ISN
-	bool "Disable sleep instruction"
-	default n
-	depends on ARC_DBG
-	help
-	  Disables the sleep instruction in the idle loop, and burn cycles
-	  instead. This is required to (partially) work around a timing
-	  inconsistency issue with nSIM
-
 config CMDLINE_UBOOT
 	bool "Support U-boot kernel command line passing"
 	default n

arch/arc/kernel/process.c

@@ -43,12 +43,8 @@ SYSCALL_DEFINE0(arc_gettls)
 
 void arch_cpu_idle(void)
 {
-#ifndef CONFIG_ARC_DISABLE_SLEEP_ISN
 	/* sleep, but enable all interrupts before committing */
 	__asm__("sleep 0x3");
-#else
-	local_irq_enable();
-#endif
 }
 
 asmlinkage void ret_from_fork(void);