pci: layerscape: fix pci_iommu_extra hotplug

We can have many pci hotplug groups, each introduced
by a "pci@<addr>" token such as,

  pci_iommu_extra=pci@0x3600000,1.0.0,hp,pci@0x3700000,1.0.0,hp,
                  pci@0x3800000,1.0.0,hp,pci@0x3900000,1.0.0,hp

Without this fix, we have the error:
  Added iommu map for hotplug 1.0.0
  ERROR: invalid action in extra iommu entry
  ERROR: invalid action in extra iommu entry
  ERROR: invalid action in extra iommu entry

Fixes: 2a5bbb13cc ("pci: layerscape: add a way of specifying additional iommu mappings")
Signed-off-by: Vincent Jardin <vjardin@free.fr>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>

drivers/pci/pcie_layerscape_fixup.c

@@ -319,6 +319,11 @@ static struct extra_iommu_entry *get_extra_iommu_ents(void *blob,
 			/* Hot-plug entry */
 			entries[i].action = EXTRA_IOMMU_ENTRY_HOTPLUG;
 			p += 2;
+			/* Skip the comma separator so it check the
+			 * next "pci@" group.
+			 */
+			if (*p == ',')
+				p++;
 		} else if (!strncmp(p, "vfs", 3) ||
 			   !strncmp(p, "noari_vfs", 9)) {
 			/* VFs or VFs with ARI disabled entry */