update for v1.2.1

[yk-fujii]

This release (1.2.1) contains the following update from 1.1.1

• Fix the starting order issue(#1) of not displaying properly when connecting two cameras to one Deserializer
  • Images are output normally regardless of the order in which the cameras are started.
  • Regarding the Xavier Devkit, R35.1 supports up to 6 camera connections, so R32.6.1 also supports 6 cameras.
  • For Orin and XavierDevKit, in environments where C1 and C2 cameras coexist, up to one each is supported.