hwlat: Select RING_BUFFER

hwlat detector uses the RING_BUFFER so it needs to be selected.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/misc/Kconfig

@@ -79,6 +79,7 @@ config IBM_ASM
 config HWLAT_DETECTOR
 	tristate "Testing module to detect hardware-induced latencies"
 	depends on DEBUG_FS
+	select RING_BUFFER
 	default m
 	---help---
 	  A simple hardware latency detector. Use this module to detect