iwlwifi: dbg_ini: use linked list to store debug TLVs

Use a linked list to maintain the debug TLVs instead of a single buffer.
This way, the driver does not need to iterate over the binary file twice
and allocates smaller chunks of memory. Also, in case one allocation
fails the driver will work with the partial configuration instead of
aborting the entire debug configuration.

Signed-off-by: Shahar S Matityahu <shahar.s.matityahu@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>