docs/fingerprint: Fix the path of fputils.py
One partner reported that the script is not there.
TEST=View it.
BRANCH=none
@@ -474,7 +474,7 @@ sensor (in nocturne), not the FPC 1025 sensor (hatch).
Convert the buffer in proprietary format into png:
```bash
-(dut) $ /opt/fpc/fputils.py /tmp/fp.raw --png
+(dut) $ /usr/local/opt/fpc/fputils.py /tmp/fp.raw --png
Extraction found 2 images
Wrote /tmp/fp.0.png (14085 bytes)
Wrote /tmp/fp.1.png (14025 bytes)
