Staging: iio: industrialio-trigger.c: minor fixups

We needed to include a header file that declared the functions that are
being exported in this file.

Also fix up an indentation problem, and some sparse warnings.

Cc: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/industrialio-trigger.c

@@ -18,6 +18,7 @@
 
 #include "iio.h"
 #include "trigger.h"
+#include "trigger_consumer.h"
 
 /* RFC - Question of approach
  * Make the common case (single sensor single trigger)
@@ -334,7 +335,7 @@ static ssize_t iio_trigger_write_current(struct device *dev,
 	return len;
 }
 
-DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
+static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 		   iio_trigger_read_current,
 		   iio_trigger_write_current);