clock: msm: Add usb2_phy_sleep_clk to USB HS PHY device

The gcc_usb2{a,b}_phy_sleep_clk is better suited to be
handled by the USB HS PHY driver rather than by the SSUSB
controller. Add the device mapping entries for MSM8974,
APQ8084, and MDM9630 targets.

A later change will remove the mapping to the SSUSB device
once the driver's expectation is removed.

Change-Id: I528e73d5e13c22c1a4ee6b37ddfe73d6747c7b6f
Signed-off-by: Jack Pham <jackp@codeaurora.org>