iwlwifi: mvm: add IML/ROM information to the assertion dumps

Dump the IML/ROM error code and data, which are read from some
registers, when printing an assertion dump.  This makes it easier to
debug IML/ROM errors.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200424194456.a522161a7372.I2a65ee35a5e0242f8a0e106f126356dff81ef59d@changeid