clk: qcom: smd-rpm: simplify XO_BUFFER clocks definitions

Remove the duplication between the names of the normal and active-only
XO_BUFFER and XO_BUFFER_PINCTRL clocks by using preprocessor logic to
add _a suffix.

Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221209164855.128798-15-dmitry.baryshkov@linaro.org