phy: tegra: xusb: Don't warn on probe defer

Deferred probe is an expected return value for tegra_fuse_readl().
Given that the driver deals with it properly, there's no need to
output a warning that may potentially confuse users.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>