Fix misra rule 17-7 for ddsc/ddsrt/cdr.

[Splinter1984]

This addresses rule 17-7.

The value returned by a function having non-void return type shall be used

Most of this changes it is just (void) cast. Except few of them.

https://github.com/Splinter1984/cyclonedds/blob/18784c7b8985e747d450d82e187b66b94568545d/src/core/ddsc/src/dds_rhc_default.c#L623-L624

https://github.com/Splinter1984/cyclonedds/blob/18784c7b8985e747d450d82e187b66b94568545d/src/core/ddsc/src/dds_rhc_default.c#L630-L631