ARM: integrator_cp: fix build failure

arch/arm/mach-integrator/integrator_cp.c:272:32: error: 'of_aliases'
undeclared (first use in this function)

Move the OF-only timer init under #ifdef CONFIG_OF, just like
integrator_ap has it.

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