Changes

bts: as_rsl_meas_res(): do not expect dummy UL SACCH

We're now populating the UL SACCH cache before establishing a
decicated channel in f_est_dchan(), so this special case is
no longer needed and can be safely removed.

Change-Id: I6eeee2876a76d41ab453af4c7724173fea773b83
Related: I4781fe7539e64e77d594e84f905646c127f46b64
Related: OS#6933