The BayTrail and CherryTrail platforms provide platform clocks
through their Power Management Controller (PMC).

The SoC supports up to 6 clocks (PMC_PLT_CLK[0..5]) with a
frequency of either 19.2 MHz (PLL) or 25 MHz (XTAL) for BayTrail
and a frequency of 19.2 MHz (XTAL) for CherryTrail. These clocks
are available for general system use, where appropriate, and each
have Control & Frequency register fields associated with them.

Port from legacy by Pierre Bossart, integration in clock framework
by Irina Tirdea

Signed-off-by: Irina Tirdea
Signed-off-by: Pierre-Louis Bossart
Acked-by: Andy Shevchenko
Signed-off-by: Stephen Boyd