usb: phy: qusb: Fix incorrect clock assignment

The clk_get() of the AHB clock was incorrectly assigned
to the PHY reset variable. It only appeared to work before
because the QMP PHY also happens to enable this clock
which allows the CSR register accesses to go through.

Change-Id: I2d1ddee2e4e1f8490ba230e9b91e1dcf609d662a
Signed-off-by: Jack Pham <jackp@codeaurora.org>