The Tegra clock driver is initialized during the ARM machine descriptor's
.init_irq() hook. It can't be initialized earlier, since dynamic memory
usage is required. It can't be initialized later, since the .init_timer()
hook needs the clocks initialized. However, at this time, udelay()
doesn't work.

The Tegra clock initialization table may enable some PLLs. Enabling a PLL
may require usage of udelay(). Hence, this can't happen right when the
clock driver is initialized.

To solve this, separate the clock driver initialization from the clock
table processing, so they can execute at separate times.
Signed-off-by: Stephen Warren <swarren@nvidia.com>