ARM: ux500: board-mop500: remove unused pin modes

Removes the following warnings:

arch/arm/mach-ux500/board-mop500-pins.c:51:6: warning: 'slpm_in_nopull_wkup' defined but not used [-Wunused-variable]
arch/arm/mach-ux500/board-mop500-pins.c:63:6: warning: 'slpm_out_lo_wkup' defined but not used [-Wunused-variable]

Signed-off-by: Olof Johansson <olof@lixom.net>
Cc: Linus Walleij <linux.walleij@linaro.org>