edge: Select implementation by mode in rlc_data_to_dl_append

Currently the GPRS data block encoding is applied to every
coding scheme, even if an MCS is selected.

This commit renames the actual encoding function to
rlc_data_to_dl_append_gprs (not exported) and puts
selection code into Encoding::rlc_data_to_dl_append. This
requires an additional cs argument.

Sponsored-by: On-Waves ehf
4 files changed