b43: update list and code making a selection of firmware files

Clean ucode selection, fix choice of firmware for LCN, drop some goto-s,
add new devices.
Tested on 14e4:4312, 14e4:4315, 14e4:4328, 14e4:432b, 14e4:4353.

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