msm: clock-8x60: Gate smi_2x_axi_clk off when smi_clk is disabled

Take ownership of smi_2x_axi_clk which was previous left enabled
at all times. The rate of smi_2x_axi_clk is still controlled by
the RPM and influenced by smi_clk, but the branch enable is now
controlled locally. Prior to enabling smi_clk (ie. sending a rate
to its RPM resource), the smi_2x_axi_clk must be enabled.
Therefore, it's marked as a dependency for smi_clk.

Signed-off-by: Matt Wagantall <mattw@codeaurora.org>