powerpc/pci: export pcibios_free_controller()

Export pcibios_free_controller(), so it can be used by the cxl module to
free virtual PHBs.

Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/pci-common.c

@@ -100,6 +100,7 @@ void pcibios_free_controller(struct pci_controller *phb)
 	if (phb->is_dynamic)
 		kfree(phb);
 }
+EXPORT_SYMBOL_GPL(pcibios_free_controller);
 
 /*
  * The function is used to return the minimal alignment