clk: qcom: Add spmi_pmic clock divider support

Clkdiv module provides a clock output on the PMIC with CXO as
the source. This clock can be routed through PMIC GPIOs. Add
a device driver to configure this clkdiv module.

Signed-off-by: Tirupathi Reddy <tirupath@codeaurora.org>
[sboyd: Simplified code and moved to devm clk provider APIs]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>