sched/Kconfig: Fix spelling mistake in user-visible help text

Fix a spelling mistake in the help text for PREEMPT_RT.
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/157204450499.10518.4542293884417101528.stgit@srivatsa-ubuntu

kernel/Kconfig.preempt

@@ -65,7 +65,7 @@ config PREEMPT_RT
 	  preemptible priority-inheritance aware variants, enforcing
 	  interrupt threading and introducing mechanisms to break up long
 	  non-preemptible sections. This makes the kernel, except for very
-	  low level and critical code pathes (entry code, scheduler, low
+	  low level and critical code paths (entry code, scheduler, low
 	  level interrupt handling) fully preemptible and brings most
 	  execution contexts under scheduler control.