clk: qcom: smd-rpm: Switch to parent_data

Switch to parent_data and with that fix the longstanding issue where
if there wasn't a clock precisely named "xo_board", rpmcc would not play
along well. This started to show lately when "xo_board" was being changed to
"xo-board" so as to align with DTS naming spec.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20210524225456.398817-1-konrad.dybcio@somainline.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>