leds: aat1290: Remove unused field 'torch_brightness' from 'struct aat1290_led'

In 'struct aat1290_led', the 'torch_brightness' field is unused. Remove it.

Found with cppcheck, unusedStructMember.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/f7c8c22242544b11e95d9a77d7d0ea17f5a24fd5.1714318454.git.christophe.jaillet@wanadoo.frSigned-off-by: Lee Jones <lee@kernel.org>

drivers/leds/flash/leds-aat1290.c

@@ -77,8 +77,6 @@ struct aat1290_led {
 	int *mm_current_scale;
 	/* device mode */
 	bool movie_mode;
-	/* brightness cache */
-	unsigned int torch_brightness;
 };
 
 static struct aat1290_led *fled_cdev_to_led(