iio:trigger:sysfs Move out of staging.

This simple driver is rather useful. No issues about its interface
have been raised for some time hence the proposal to move it out
of staging.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
new file mode 100644
index 0000000..a4e68db
--- /dev/null
+++ b/drivers/iio/trigger/Kconfig
@@ -0,0 +1,17 @@
+#
+# Industrial I/O standalone triggers
+#
+menu "Triggers - standalone"
+
+config IIO_SYSFS_TRIGGER
+	tristate "SYSFS trigger"
+	depends on SYSFS
+	select IRQ_WORK
+	help
+	  Provides support for using SYSFS entry as IIO triggers.
+	  If unsure, say N (but it's safe to say "Y").
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iio-trig-sysfs.
+
+endmenu