orinoco: Extend hermes_dld routines for Agere firmware

Add programming initialisation and termination functions.
Add checks to avoid overrunning the firmware image or PDA areas.
Extra algorithm to program PDA values using defaults where necessary.

Signed-off-by: David Kilroy <kilroyd@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>