iwlwifi: move all ucode routines to iwl-ucode.c

The routines dealing with the ucode are spread through several files.
Move them all to the same file and create a iwl-ucode.h file with the
ucode file definitions.

Signed-off-by: Don Fry <donald.h.fry@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>