stm class: stm_console: Add kernel-console-over-stm driver

This is a simple stm_source class device driver (kernelspace stm trace
source) that registers a console and sends kernel messages over STM
devices.

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/stm/Makefile

@@ -3,3 +3,7 @@ obj-$(CONFIG_STM)	+= stm_core.o
 stm_core-y		:= core.o policy.o
 
 obj-$(CONFIG_STM_DUMMY)	+= dummy_stm.o
+
+obj-$(CONFIG_STM_SOURCE_CONSOLE)	+= stm_console.o
+
+stm_console-y		:= console.o