Add a new region type that allows us to dump the PCI config space.
This is mostly the same as dumping a memory region, but reading from
the device's config space instead.

In order to make this generic and independent of the trans type, we
make a function called iwl_dump_ini_config_iter() that calls a new op
in the transport to read its config space.

Change-Id: I15151bddf589f13b0e0a45c28b96bbcd73bcfdeb
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>