MFC 296552,296596,296603,296624,296627: Fixes related to memory windows.

296552:
cxgbe(4): Rename regwin_lock to reg_lock. It is used to protect access
to indirect registers only.

296596:
cxgbe(4): Allow the addr/len pair that is being validated in
validate_mem_range to span multiple memory types. Update
validate_mt_off_len to use validate_mem_range.

296603:
cxgbe(4): Add general purpose routines that offer safe access to the
chip's memory windows. Convert existing users of these windows to the
new routines.

296624:
cxgbe(4): Fix bug in r296603. The memory window needs to be
repositioned if the start address isn't in the window already. One
of the bounds check used the end address instead.

296627:
cxgbe(4): Improvements to the code that deals with the firmware's log.

• Query the location of the log very early during attach. Refresh the location later after establishing contact with the firmware.
• Save the log's location as a flat address in devlog_params.
• Use a memory window instead of backdoor access to the EDC/MC to read the log.

Sponsored by: Chelsio Communications