ARM: at91: Fix typo in restart code panic message

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable <stable@vger.kernel.org> # 3.4+