net: wwan: iosm: Fix htmldocs warnings

Fixes .rst file warnings seen on linux-next build.

Fixes: f7af616c

 ("net: iosm: infrastructure")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: M Chetan Kumar <m.chetan.kumar@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>