Checksum coverage values larger than 65535 for UDPLite are invalid.
Check for this when the user calls setsockopt using UDPLITE_{SEND,RECV}CSCOV.

Reviewed by: kevlo
MFC after: 3 days


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272263 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f