iwlwifi: pcie: add context information support

Context information structure is going to be used in a000
devices for firmware self init.

The self init includes firmware self loading from DRAM by
ROM.
This means the TFH relevant firmware loading can be cleaned up.

The firmware loading includes the paging memory as well, so op
mode can stop initializing the paging and sending the DRAM_BLOCK_CMD.

Firmware is doing RFH, TFH and SCD configuration, while driver
only fills the required configurations and addresses in the
context information structure.

The only remaining access to RFH is the write pointer, which
is updated upon alive interrupt after FW configured the RFH.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>