misc: fix ip6_neighbor_cmd

misc: fix ip6_neighbor_cmd

The option parsing loop had "break" statements included in each
'if (unformat (line_input, "this-option ...") option_values=xxx;'
statement.

Result: the code would silently ignore all but the first
option. Probably broken forever, not easy to spot because the code
looks OK even though it's badly broken.

Manual cherrypick: the function name has changed, the code has
moved to a different file, and the MAINTAINERS file entry doesn't
exist in 19.08.

Type: fix

Signed-off-by: Dave Barach <[email protected]>
(cherry picked from commit 7249b90ab21c20138907e692dcb6032aea9e2f0f)
Change-Id: Ie06bb083645302848a19ecc9ad2934927de01f62