libteam: Use u8 for put/get TEAM_ATTR_OPTION_TYPE

Use the same type in libteam and kernel for TEAM_ATTR_OPTION_TYPE.
The kernel uses a 8 bit integer (u8).

Signed-off-by: Jonas Johansson <jonasj76@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>