phy: phy-snps-eusb2: make repeater optional

As described in the device tree bindings, it's not necessary for the
SNPS eUSB2 phy to be connected to a repeater. In configurations where
there are such instances, the driver probing fails and the usb
controller does not work.

Make the repeater optional to avoid that, which also lets us use
the eUSB2 phy when it's connected to a repeater that is not configurable
by the kernel (for example it's missing a driver), as long as it has
been configured beforehand (usually by the bootloader).

Signed-off-by: Ivaylo Ivanov <ivo.ivanov.ivanov1@gmail.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250504144527.1723980-7-ivo.ivanov.ivanov1@gmail.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>