SUNRPC: allow /proc entries without CONFIG_SUNRPC_DEBUG

If we want /proc/sys/sunrpc the current kernel also drags in other debug
features which we don't really want. Instead, we should always show the
following entries:

/proc/sys/sunrpc/udp_slot_table_entries
/proc/sys/sunrpc/tcp_slot_table_entries
/proc/sys/sunrpc/tcp_max_slot_table_entries
/proc/sys/sunrpc/min_resvport
/proc/sys/sunrpc/max_resvport
/proc/sys/sunrpc/tcp_fin_timeout

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Thomas Preston <thomas.preston@codethink.co.uk>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>