auxdisplay: img-ascii-lcd: Remove an unused field in struct img_ascii_lcd_ctx

Remove 'cfg' from struct img_ascii_lcd_ctx. It is unused since commit
7e76aece6f03 ("auxdisplay: Extract character line display core support")

Signed-off-by: Christophe JAILLET <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Andy Shevchenko <[e-mail]>

drivers/auxdisplay/img-ascii-lcd.c

···
  * @base: the base address of the LCD registers
  * @regmap: the regmap through which LCD registers are accessed
  * @offset: the offset within regmap to the start of the LCD registers
- * @cfg: pointer to the LCD model configuration
  */
 struct img_ascii_lcd_ctx {
 	struct linedisp linedisp;
···
 		struct regmap *regmap;
 	};
 	u32 offset;
-	const struct img_ascii_lcd_config *cfg;
 };
 
 /*