Sample Rate is Halved When Using BLADERF_FEATURE_OVERSAMPLE

[cwozny]

When using the new oversample feature, the sample rate seems to be effectively half of what gets set in bladerf_set_sample_rate(). This was tested by using a signal generator and feeding in a pulsed waveform with a 48 us duration. With oversample feature enabled, 8-bit resolution, and 50 Msps sampling rate, the pulse duration was incorrectly being measured as ~24 us. With default feature enabled, 8-bit resolution, and 50 Msps sample rate, the pulse duration was correctly being measured as ~48 us.

This was tested minutes apart and the only code delta was in this commit: cwozny/sdr_channelizer@a36a758

I also tried to enable oversampling after setting the sampling rate due to an issue that @rthomp10 fixed with commit 86d68ee, but this didn't correct the sampling rate either.

Plots included for reference, note the time per division showing the pulse duration being halved when using oversampling.

Board: Nuand bladeRF 2.0 (bladerf2)
Serial #: xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
VCTCXO DAC calibration: 0x230b
FPGA size: 77 KLE
FPGA loaded: yes
Flash size: 64 Mbit
USB bus: 0
USB address: 1
USB speed: SuperSpeed
Backend: libusb
Instance: 0

bladeRF-cli version: 1.9.0-git-41ef6346
libbladeRF version: 2.5.0-git-41ef6346

Firmware version: 2.4.0-git-a3d5c55f
FPGA version: 0.15.0