iwlwifi: pcie: add firmware monitor capabilities

This allows to use the firmware monitor. This capability
uses a lot of contiguous memory (up to 64MB), so make its
usage module parameter dependent.

The driver will try to allocate as much contiguous memory
as possible downgrading its requirements until the
allocation succeeds.

Dump this data into the fw-error dump file when an error
happens.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>