microblaze: Add missing double apostrophe in Kconfig

Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/Kconfig

@@ -90,7 +90,7 @@ source "arch/microblaze/platform/Kconfig.platform"
 
 menu "Processor type and features"
 
-source kernel/time/Kconfig
+source "kernel/time/Kconfig"
 
 source "kernel/Kconfig.preempt"