iio: Add missing modifier names to core

some are documented, others are in iio_event_monitor.c which
was recently moved from staging

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/industrialio-core.c

@@ -81,6 +81,14 @@ static const char * const iio_modifier_names[] = {
 	[IIO_MOD_X] = "x",
 	[IIO_MOD_Y] = "y",
 	[IIO_MOD_Z] = "z",
+	[IIO_MOD_X_AND_Y] = "x&y",
+	[IIO_MOD_X_AND_Z] = "x&z",
+	[IIO_MOD_Y_AND_Z] = "y&z",
+	[IIO_MOD_X_AND_Y_AND_Z] = "x&y&z",
+	[IIO_MOD_X_OR_Y] = "x|y",
+	[IIO_MOD_X_OR_Z] = "x|z",
+	[IIO_MOD_Y_OR_Z] = "y|z",
+	[IIO_MOD_X_OR_Y_OR_Z] = "x|y|z",
 	[IIO_MOD_ROOT_SUM_SQUARED_X_Y] = "sqrt(x^2+y^2)",
 	[IIO_MOD_SUM_SQUARED_X_Y_Z] = "x^2+y^2+z^2",
 	[IIO_MOD_LIGHT_BOTH] = "both",