arm64: defconfig: remove CONFIG_USB_QCOM_8X16_PHY

No Qualcomm SoC requires the "phy-qcom-8x16-usb.c" USB phy driver
support any more.  Remove the code, and remove the config option
from the arm64 defconfig.
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

arch/arm64/configs/defconfig

@@ -437,7 +437,6 @@ CONFIG_USB_CHIPIDEA_ULPI=y
 CONFIG_USB_ISP1760=y
 CONFIG_USB_HSIC_USB3503=y
 CONFIG_NOP_USB_XCEIV=y
-CONFIG_USB_QCOM_8X16_PHY=y
 CONFIG_USB_ULPI=y
 CONFIG_USB_GADGET=y
 CONFIG_USB_RENESAS_USBHS_UDC=m