pinctrl: single: fix spelling mistakes on "Ivalid"

Trivial fixe to spelling mistake "Ivalid" to "Invalid" in
dev_err  error message.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>