ARM: OMAP2+: AM33XX: clock data: Add clkdev alias for cpu0

Add AM335x cpu0 clock entry to the corresponding clock data file. This
is useful in getting the correct mpu clock pointer to change the cpu
frequency in cpufreq driver.

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
[paul@pwsan.com: changed patch subject]
Signed-off-by: Paul Walmsley <paul@pwsan.com>