Use the word "LinuxKPI" instead of "Linux compatibility", to not confuse with

user-space Linux compatibility support. No functional change.

MFC after:	1 week
Sponsored by:	Mellanox Technologies // NVIDIA Networking

sys/kern/kern_intr.c

@@ -783,8 +783,8 @@ intr_handler_barrier(struct intr_handler *handler)
  * Sleep until an ithread finishes executing an interrupt handler.
  *
  * XXX Doesn't currently handle interrupt filters or fast interrupt
- * handlers.  This is intended for compatibility with linux drivers
- * only.  Do not use in BSD code.
+ * handlers. This is intended for LinuxKPI drivers only.
+ * Do not use in BSD code.
  */
 void
 _intr_drain(int irq)

sys/sys/interrupt.h

@@ -190,7 +190,7 @@ int	intr_event_resume_handler(void *cookie);
 int	intr_getaffinity(int irq, int mode, void *mask);
 void	*intr_handler_source(void *cookie);
 int	intr_setaffinity(int irq, int mode, void *mask);
-void	_intr_drain(int irq);  /* Linux compat only. */
+void	_intr_drain(int irq);  /* LinuxKPI only. */
 int	swi_add(struct intr_event **eventp, const char *name,
 	    driver_intr_t handler, void *arg, int pri, enum intr_type flags,
 	    void **cookiep);