vco and pll are very closely bound to each other,
"vco needs to program: mode, m & n" and "pll needs to program p",
both share common enable/disable logic and registers.
This patch adds in support for this type of clock.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Reviewed-by: Mike Turquette <mturquette@linaro.org>