clk: qcom: Add MSM8916 Global Clock Controller support

This patch adds support for the global clock controller found on the MSM8916
based devices. It allows the various device drivers to probe and control
their clocks and resets.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
[sboyd@codeaurora.org: Removed NULL entry from parent_maps]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>