msm: clock-8084: Make set rate go through usb hsic ahb clock

usb_hsic_ahb_clk_src has two branch clocks: gcc_usb_hsic_ahb_clk
and gcc_periph_noc_usb_hsic_ahb_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_usb_hsic_ahb_clk to 0 to allow clk_set_rate on this clock
to simplify the clock control.

Change-Id: I2f5a53e22856a6d7b7f1d72d79e686390dea8f2e
Signed-off-by: Tianyi Gou <tgou@codeaurora.org>