uboot-phytec

rockchip: rk3288: use ARM arch timer instead of rk_timer

We prefer to use ARM arch timer instead of rockchip timer, so that
we are using the same timer for SPL, U-Boot and Kernel, which will
make things simple and easy to track to boot time.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>