net: llc: Fix kerneldoc warnings

net/llc/llc_conn.c:917: warning: Function parameter or member 'kern' not described in 'llc_sk_alloc'
net/llc/llc_conn.c:917: warning: Function parameter or member 'prot' not described in 'llc_sk_alloc'

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20201028004644.929997-1-andrew@lunn.ch


Signed-off-by: Jakub Kicinski <kuba@kernel.org>