nios2: use generic strncpy_from_user() and strnlen_user()

This change enables the generic strncpy_from_user() and strnlen_user()

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index 51a56c8..a72d5f0 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -6,6 +6,8 @@
 	select GENERIC_CPU_DEVICES
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
+	select GENERIC_STRNCPY_FROM_USER
+	select GENERIC_STRNLEN_USER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_KGDB
 	select IRQ_DOMAIN