PCI: dwc: designware: Handle ->host_init() failures

In several dwc-based drivers, ->host_init() can fail, so make sure to
propagate and handle this to avoid continuing operation of a driver or
hardware in an invalid state.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Joao Pinto <jpinto@synopsys.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>