pinctrl: qcom: General Purpose clocks for apq8064

Add support for general purpose (GP) clocks
for apq8064

DT binding documentation updated for
qcom,apq8064-pinctrl general purpose (GP) clocks.

Signed-off-by: Vinay Simha BN <simhavcs@gmail.com>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>