dm: Use dev_get_addr() where possible

This is a convenient way for a driver to get the hardware address of a
device, when regmap or syscon are not being used. Change existing callers
to use it as an example to others.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>