sunrpc: move sunrpc_table and proc routines above

No need to do a forward declaration for sunrpc_table, just move
the sysctls up as everyone else does it. This will make the next
change easier to read. This change produces no functional changes.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>