CRIS: Fix missing NR_CPUS in menuconfig

The time Kconfig expects that NR_CPUS is defined.

This patch removes this config warning:
"kernel/time/Kconfig:163:warning: range is invalid"

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index 52731e2..4a03911 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -57,6 +57,10 @@
 	int
 	default 100
 
+config NR_CPUS
+	int
+	default "1"
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"