clk: qcom: Change gcc_usb3_phy_pipe_clk to gate_clk

gcc_usb3_phy_pipe_clk's source could be dynamically gated off at any
time. Thus checking branch_clk status bit could result in stuck on/off
warnings. Since the HW design can handle clock input glitch, model
gcc_usb3_phy_pipe_clk as gate clock instead of branch_clk.

Also add gcc_usb3phy_phy_reset for asserting reset bit previously
associated to gcc_usb3_phy_pipe_clk branch.

Change-Id: Id26c4c69af8b8b66f83fd6e160e4080494f25191
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>