clk: qcom: gcc-sm8550: Add the missing RETAIN_FF_ENABLE GDSC flag

All of the 8550's GCC GDSCs can and should use the retain registers so
as not to lose their state when entering lower power modes.

Fixes: 955f2ea3 ("clk: qcom: Add GCC driver for SM8550")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20231218-topic-8550_fixes-v1-3-ce1272d77540@linaro.org


Signed-off-by: Bjorn Andersson <andersson@kernel.org>