powerpc: Make set_dabr() a ppc_md function

Move pSeries specific code in set_dabr() into a ppc_md function, this will
allow us to keep plpar_wrappers.h private to platforms/pseries.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
diff --git a/include/asm-powerpc/machdep.h b/include/asm-powerpc/machdep.h
index 451b345..629ca96 100644
--- a/include/asm-powerpc/machdep.h
+++ b/include/asm-powerpc/machdep.h
@@ -80,6 +80,7 @@
 	void		(*iommu_dev_setup)(struct pci_dev *dev);
 	void		(*iommu_bus_setup)(struct pci_bus *bus);
 	void		(*irq_bus_setup)(struct pci_bus *bus);
+	int		(*set_dabr)(unsigned long dabr);
 #endif
 
 	int		(*probe)(int platform);