serial: sh-sci: Fix compatible string in DT bindings example

Remove the -generic suffix from the compatible string in the serial port
DT bindings example.

Cc: devicetree@vger.kernel.org
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>