b43: be more user friendly with PHY info

First of all, use PHY names instead of magic numbers. It should make
configuring kernel easier in case of not enabled PHY type support.
Secondly, always print info about PHY. This is really basic info about
hardware and quite important for the support level.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>