PCI: exynos: Propagate errors for optional PHYs

devm_of_phy_get() can fail for a number of reasons besides probe
deferral. It can for example return -ENOMEM if it runs out of memory as
it tries to allocate devres structures. Propagating only -EPROBE_DEFER
is problematic because it results in these legitimately fatal errors
being treated as "PHY not specified in DT".

What we really want is to ignore the optional PHYs only if they have not
been specified in DT. devm_of_phy_get() returns -ENODEV in this case, so
that's the special case that we need to handle. So we propagate all
errors, except -ENODEV, so that real failures will still cause the
driver to fail probe.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>