The usb_get_maximum_speed() function is part of the usb-common module,
so enable it by selecting the corresponding Kconfig symbol.

While at it, also make sure to depend on USB_SUPPORT because USB_PHY
requires that. This can lead to Kconfig conflicts if USB_SUPPORT is not
enabled while attempting to enable PHY_TEGRA_XUSB.
Reported-by: kbuild test robot <lkp@intel.com>
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20200330101038.2422389-1-thierry.reding@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>