Add Guvenc as maintainer for Shared Memory Communications (SMC)
Sockets.

Cc: Julian Wiedmann <jwi@linux.ibm.com>
Acked-by: NGuvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>