This adds the PHY reset into a common error path of
imx6_pcie_establish_link(), deduplicating some of the debug prints.  Also
reduce the severity of the "no-link" message in the one place where it is
expected to be hit when no peripheral is attached.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>