of: remove asm/of_platform.h

Only thing left in it is of_instantiate_rtc() which can be moved to
asm/prom.h on PowerPC and is unused in microblaze.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index f864722..da7dd63 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -117,5 +117,7 @@
 struct pci_dev;
 extern int of_irq_map_pci(struct pci_dev *pdev, struct of_irq *out_irq);
 
+extern void of_instantiate_rtc(void);
+
 #endif /* __KERNEL__ */
 #endif /* _POWERPC_PROM_H */