pinctrl: mvebu: armada-xp: fix functions of MPP48

There was a mistake in the definition of the functions for MPP48 on
Marvell Armada XP. The second function is dev(clkout), and not tclk.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: <stable@vger.kernel.org> # v3.7+
Fixes: 463e270f ("pinctrl: mvebu: add pinctrl driver for Armada XP")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>