iio: mxs: Remove unused struct mxs_lradc_chan

This structure definition seems to be some kind of remnant from
previous development that accidentally made it mainline. Remove
it as it's unused.

Remove unused "enable" field from struct mxs_lradc as well. This
seems to be remnant of early development too.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/adc/mxs-lradc.c

@@ -75,11 +75,6 @@ static const char * const mxs_lradc_irq_name[] = {
 	"mxs-lradc-button1",
 };
 
-struct mxs_lradc_chan {
-	uint8_t				slot;
-	uint8_t				flags;
-};
-
 struct mxs_lradc {
 	struct device		*dev;
 	void __iomem		*base;
@@ -90,8 +85,6 @@ struct mxs_lradc {
 
 	struct mutex		lock;
 
-	uint8_t			enable;
-
 	struct completion	completion;
 };