net: wwan: iosm: correct devlink extra params

1. Removed driver specific extra params like download_region,
address & region_count. The required information is passed
as part of flash API.
2. IOSM Devlink documentation updated to reflect the same.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: iosm: devlink fw flashing & cd collection documentation

Documents devlink params, fw update & cd collection commands
and its usage.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>