usb: host: ehci-exynos: Remove unnecessary usb-phy support

Now that we have completely moved from older USB-PHY drivers
to newer GENERIC-PHY drivers for PHYs available with USB controllers
on Exynos series of SoCs, we can remove the support for the same
in our host drivers too.

We also defer the probe for our host in case we end up getting
EPROBE_DEFER error when getting PHYs.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>