ARM: dts: omap: fix OMAP3 CM-T3x OF graph video connectors

The OMAP3 CM-T3x based boards define 2 /connector nodes for S-Video and
DVI output. However, since they have the same node name, the S-Video
connector overwritten. This leaves a dangling graph connection which
gives the following warning:

arch/arm/boot/dts/omap3-sbc-t3517.dtb: Warning (graph_endpoint):
/ocp@68000000/dss@48050000/encoder@48050c00/port/endpoint: graph
connection to node '/connector/port/endpoint' is not bidirectional

Fix this by renaming the nodes to s-video-connector and dvi-connector.

Cc: "Benoît Cousson" <bcousson@baylibre.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>