of: move of_address_to_resource and of_iomap declarations from sparc

Move of_address_to_resource and of_iomap declarations to common code. These
only differ on sparc, but the declarations are the same and don't need to
be in arch header.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Grant Likely <grant.likely@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org