stm class: Make dummy's master/channel ranges configurable

To allow for more flexible testing of the stm class, make it possible
to specify the ranges of masters and channels that the dummy_stm devices
cover. This is done via module parameters.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>

include/uapi/linux/stm.h

@@ -12,6 +12,10 @@
 
 #include <linux/types.h>
 
+/* Maximum allowed master and channel values */
+#define STP_MASTER_MAX	0xffff
+#define STP_CHANNEL_MAX	0xffff
+
 /**
  * struct stp_policy_id - identification for the STP policy
  * @size:	size of the structure including real id[] length