usb: dwc3: xilinx: fix error handling in zynqmp init error paths

usb: dwc3: xilinx: fix error handling in zynqmp init error paths

Fix error handling and resource cleanup i.e remove invalid
phy_exit() after failed phy_init(), route failures through
proper cleanup paths and return 0 explicitly on success.

Fixes: 84770f028fab ("usb: dwc3: Add driver for Xilinx platforms")
Cc: stable@vger.kernel.org
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Link: https://patch.msgid.link/20260519115529.2980421-1-radhey.shyam.pandey@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>