of/address: sparc: Declare of_address_to_resource() as an extern function for sparc again

This bug-fix makes sure that of_address_to_resource is defined extern for sparc
so that the sparc-specific implementation of of_address_to_resource() is once
again used when including include/linux/of_address.h in a sparc context. A
number of drivers in mainline relies on this function working for sparc.

The bug was introduced in a850a7554442f08d3e910c6eeb4ee216868dda1e, "of/address:
add empty static inlines for !CONFIG_OF". Contrary to that commit title, the
static inlines are added for !CONFIG_OF_ADDRESS, and CONFIG_OF_ADDRESS is never
defined for sparc. This is good behavior for the other functions in
include/linux/of_address.h, as the extern functions defined in
drivers/of/address.c only gets linked when OF_ADDRESS is configured. However,
for of_address_to_resource there exists a sparc-specific implementation in
arch/sparc/arch/sparc/kernel/of_device_common.c

Solution suggested by: Sam Ravnborg <[e-mail]>

Signed-off-by: Andreas Larsson <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

arch/sparc/include/asm/prom.h

···
 extern void irq_trans_init(struct device_node *dp);
 extern char *build_path_component(struct device_node *dp);
 
+/* SPARC has a local implementation */
+extern int of_address_to_resource(struct device_node *dev, int index,
+				  struct resource *r);
+#define of_address_to_resource of_address_to_resource
+
 #endif /* __KERNEL__ */
 #endif /* _SPARC_PROM_H */

include/linux/of_address.h

···
 #endif
 
 #else /* CONFIG_OF_ADDRESS */
+#ifndef of_address_to_resource
 static inline int of_address_to_resource(struct device_node *dev, int index,
 					 struct resource *r)
 {
 	return -EINVAL;
 }
+#endif
 static inline struct device_node *of_find_matching_node_by_address(
 					struct device_node *from,
 					const struct of_device_id *matches,