net: fix kernel-doc warnings for socket.c

Fix kernel-doc warnings by moving the kernel-doc notation to be
immediately above the functions that it describes.

Fixes these warnings for sock_sendmsg() and sock_recvmsg():

../net/socket.c:658: warning: Excess function parameter 'sock' description in 'INDIRECT_CALLABLE_DECLARE'
../net/socket.c:658: warning: Excess function parameter 'msg' description in 'INDIRECT_CALLABLE_DECLARE'
../net/socket.c:889: warning: Excess function parameter 'sock' description in 'INDIRECT_CALLABLE_DECLARE'
../net/socket.c:889: warning: Excess function parameter 'msg' description in 'INDIRECT_CALLABLE_DECLARE'
../net/socket.c:889: warning: Excess function parameter 'flags' description in 'INDIRECT_CALLABLE_DECLARE'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>