msm: clock-8084: Make set rate go through usb30 sec master clock

usb30_sec_master_clk_src has two branch clocks: gcc_usb30_sec_master_clk
and gcc_sys_noc_usb3_sec_axi_clk . Since these branch clocks are
controlled by the same client driver and need to be turned on and off
at the same time, just set the sibling field of gcc_usb30_sec_master_clk
to 0 to allow clk_set_rate on this clock to simplify the clock control.

Change-Id: I6db42f68ef3a89923aeb544809efbac7234b0ee5
Signed-off-by: Tianyi Gou <tgou@codeaurora.org>