lms: Check LPBFW to set is within supported range

As of LimeSuite 618fbb9c3188b36d75ad5785a97b8887dcc468f6, it seems 5e6
is within the returned range, but LMS_SetLPFBW fails anyway.

See for more information: https://github.com/myriadrf/LimeSuite/issues/184

Change-Id: I967e7da7c0e3e8138b76733ee4a0e6311d20b62e
1 file changed