"type" is already used as a common option for all protocols. This makes
the configuration ambiguous, and Luci sees JS errors when trying to save
a MAP configuration.
Switch to "maptype" instead to avoid the conflict. MAP currently uses
"maptype" and falls back to "type" when not specified.
Signed-off-by: Remi NGUYEN VAN <remi.nguyenvan+openwrt@gmail.com>