[low-power] enhance mCslFrameRequestAheadUs calculation for RCP
#92
| Job | Run time |
|---|---|
| 14m 6s | |
| 30m 24s | |
| 30m 48s | |
| 20m 13s | |
| 9m 0s | |
| 24m 59s | |
| 30m 35s | |
| 30m 47s | |
| 31m 1s | |
| 45s | |
| 3h 42m 38s |