Update webos-connman-adapter.sh: Only load cdc_ether in case it's bui…

[Herrie82]

…lt as module

On targets outside of OSE such as LuneOS targets which use Android or Mainline Kernel, CDC_ETHER might not be built (as module), so introduce a check, to make sure that it's actually built as module, before trying to modprobe it.

Solves a continuous loop.