northbridge/amd/agesa: DEVICE_NOOP some stub functions

Use 'DEVICE_NOOP' over stub functions to reduce loc and
improve formalism.

Change-Id: I9c8d608539647cce22fb1dfbe284a6043d3d23d9
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7534
Tested-by: build bot (Jenkins)
Reviewed-by: Bruce Griffith <Bruce.Griffith@se-eng.com>
northbridge/amd/agesa/Kconfig: Trivial - correct indent

Change-Id: Ia7d9cb77f83afda66a1fe4e1228f2728c94e1c99
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7535
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Bruce Griffith <Bruce.Griffith@se-eng.com>