soc: qcom: ocmem: make iface clock optional

Some platforms such as msm8226 do not have an iface clk. Since clk_bulk
APIs don't offer to a way to treat some clocks as optional simply add
core_clk and iface_clk members to our drvdata.

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20230506-msm8226-ocmem-v3-3-79da95a2581f@z3ntu.xyz


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