ARM: OMAP2+: clock/dpll: add jitter correction behind clk_features

Currently DPLL code uses runtime cpu_is_343x checks to see if the DPLL
has freqsel fields in its control register or not. Instead, add a new
flag to the clk_features.flags and use this during runtime. Allows
eventual move of the DPLL code under clock driver.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Paul Walmsley <paul@pwsan.com>