ARC: remove stale config entry

Signed-off-by: Vineet Gupta <[email protected]>

Author: vineetgarc

arch/arc/configs/nsimosci_defconfig

@@ -26,7 +26,6 @@ CONFIG_ARC_PLAT_FPGA_LEGACY=y
 CONFIG_ARC_BOARD_ML509=y
 # CONFIG_ARC_IDE is not set
 # CONFIG_ARC_HAS_RTSC is not set
-CONFIG_ARC_DISABLE_SLEEP_ISN=y
 CONFIG_ARC_BUILTIN_DTB_NAME="nsimosci"
 # CONFIG_COMPACTION is not set
 # CONFIG_CROSS_MEMORY_ATTACH is not set