timer: Add AST2700 IBEX timer support

Add the driver for the AST2700 Ibex timer, which uses CPU
cycles as the timer count running at 200MHz.

Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
3 files changed