clk: qcom: Add support for regmap mux-div clocks

clk: qcom: Add support for regmap mux-div clocks

Add support for hardware that support switching both parent clocks and the
divider at the same time. This avoids generating intermediate frequencies
from either the old parent clock and new divider or new parent clock and
old divider combinations.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>