netconsole: use netpoll_parse_ip_addr in local_ip_store

netconsole: use netpoll_parse_ip_addr in local_ip_store

Replace manual IP address parsing with a call to netpoll_parse_ip_addr
in remote_ip_store(), simplifying the code and reducing the chance of
errors.

The error message got removed, since it is not a good practice to
pr_err() if used pass a wrong value in configfs.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>