omap4 clocks allow 1MHz leeway

With smartreflex(?) pll settings no long always match exactly
this allows match on up to 1MHz lower frequency.

Signed-off-by: Andy Green <andy.green@linaro.org>
Improve DPLL frequency rounding code

Maintain a list of successful frequency translations for any given DPLL.
Speed up frequency calculations by searching the cache first.
Do a more exhaustive search for the best possible DPLL paramters for a
new frequency.
If an exact fit is not found, return the best possible match within jitter
constraints.
Change the worst case match criteria from +/-1MHZ to +/-0.01% (on the 4460
350MHz will be off by 0.003%).

Signed-off-by: David A. Long <dave.long@linaro.org>