If OF_ADDRESS is not configured, builds can fail with errors such as

drivers/net/ethernet/hisilicon/hns_mdio.c:
	In function 'hns_mdio_bus_name':
drivers/net/ethernet/hisilicon/hns_mdio.c:411:3:
	error: implicit declaration of function 'of_translate_address'

as currently seen when building sparc:allmodconfig.

Introduce a static inline function if OF_ADDRESS is not configured to fix
the build failure. Return OF_BAD_ADDR in this case. For this to work, the
definition of OF_BAD_ADDR has to be moved outside CONFIG_OF conditional
code.

Fixes: 876133d3 ("net: hisilicon: add OF dependency")
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Frank Rowand <frank.rowand@sonymobile.com>
Signed-off-by: Rob Herring <robh@kernel.org>