metag: log core and timer frequencies from arch code

Log core clock and Meta timer frequencies during init in architecture
generic code, removing the need for equivalent log messages in SoC
specific code.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>