PCI: mvebu: Check for errors from pci_bridge_emul_init() call

Function pci_bridge_emul_init() may fail so correctly check for errors.

Link: https://lore.kernel.org/r/20211125124605.25915-3-pali@kernel.org


Fixes: 1f08673e ("PCI: mvebu: Convert to PCI emulated bridge config space")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>