leds: atmel-pwm: remove unnecessary platform_set_drvdata()

The driver core clears the driver data to NULL after device_release
or on probe failure, since commit 0998d0631001288a5974afc0b2a5f568bcdecb4d
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.

Signed-off-by: Jingoo Han <[e-mail]>
Signed-off-by: Bryan Wu <[e-mail]>

drivers/leds/leds-atmel-pwm.c

···
 		pwm_channel_free(&led->pwmc);
 	}
 
-	platform_set_drvdata(pdev, NULL);
 	return 0;
 }