backlight: ili922x: Remove invalid use of kerneldoc syntax

Kerneldoc is for documenting function arguments and return values.

Prevents warnings like:

 drivers/video/backlight/ili922x.c:127: warning: cannot understand function prototype: 'int ili922x_id = 1; '
 drivers/video/backlight/ili922x.c:136: warning: cannot understand function prototype: 'struct ili922x '

Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Software Engineering <sbabic@denx.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/video/backlight/ili922x.c

@@ -123,7 +123,7 @@
 
 #define set_tx_byte(b)		(tx_invert ? ~(b) : b)
 
-/**
+/*
  * ili922x_id - id as set by manufacturer
  */
 static int ili922x_id = 1;
@@ -132,7 +132,7 @@ module_param(ili922x_id, int, 0);
 static int tx_invert;
 module_param(tx_invert, int, 0);
 
-/**
+/*
  * driver's private structure
  */
 struct ili922x {