fft_eval: Reorder bytes from big endian (network) order to host order

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>
Convert sample dumps to network byte order

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>
fft_eval: Update usage according to linux kernel functionality

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>
fft_eval: Add support for data format without shifted samples

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>
fft_eval: Convert sample dumps to new format

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>