sur40: lower poll interval to fix occasional FPS drops to ~56 FPS

commit af766ee0 upstream.

The framerate sometimes drops below 60 Hz if the poll interval is too high.
Lowering it to the minimum of 1 ms fixes this.
Signed-off-by: Martin Kaltenbrunner <modin@yuri.at>
Signed-off-by: Florian Echtler <floe@butterbrot.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/input/touchscreen/sur40.c

@@ -126,7 +126,7 @@ struct sur40_image_header {
 #define VIDEO_PACKET_SIZE  16384
 
 /* polling interval (ms) */
-#define POLL_INTERVAL 4
+#define POLL_INTERVAL 1
 
 /* maximum number of contacts FIXME: this is a guess? */
 #define MAX_CONTACTS 64