clk: qcom: select GDSC for msm8996 gcc and mmcc

This patch selects QCOM_GDSC Kconfig for msm8996 GCC and MMCC clock
controllers, as these provide some of the gdscs on the SOC.

Also selecting this config will make it align with other drivers which
do the same.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Fixes: 52111672 ("clk: qcom: gdsc: Add GDSCs in msm8996 GCC")
Fixes: 7e824d50 ("clk: qcom: gdsc: Add mmcc gdscs for msm8996 family")
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>