ARM: integrator-cp: convert use CLKSRC_OF for timer init

Move the integrator-cp timer init to timer-sp.c and use CLKSRC_OF. There is
no reason to use the aliases, so drop them from the init code.

The integrator-cp timers are mistakenly called sp804 timers in the dts, but
in fact they are not sp804 dual timers, but single timers with the same
programming model. Fix the dts to reflect this.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>