include: up the number of max. input devices to 40.

With the Xtest virtual slave devices we have 4 devices for each MD
pointer/keyboard pair, plus the AllDevices and AllMasterDevices reserved
deviceids. It's quite easy to hit the current limit.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

include/misc.h

@@ -86,7 +86,7 @@ OF THIS SOFTWARE.
 #define MAXCLIENTS	256
 #define MAXEXTENSIONS   128
 #define MAXFORMATS	8
-#define MAXDEVICES	20 /* input devices */
+#define MAXDEVICES	40 /* input devices */
 
 #define EXTENSION_EVENT_BASE 64
 #define EXTENSION_BASE 128