Input: cyttsp - error message on boot mode exit error

Provide a proper error message when attempting to exit boot loader mode
and failing, which is something that happened to me.

Reviewed-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210408131153.3446138-5-linus.walleij@linaro.org


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>