iwlwifi: refactor common transport alloc/init code

The transport modules all need to allocate memory and set up
certain values. Refactor that code into a new common function
to share it and to simplify the error handling.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

diff --cc drivers/net/wireless/iwlwifi/Makefile
Simple merge

diff --cc drivers/net/wireless/iwlwifi/iwl-trans.c
Simple merge

diff --cc drivers/net/wireless/iwlwifi/iwl-trans.h
Simple merge

diff --cc drivers/net/wireless/iwlwifi/pcie/trans.c
Simple merge