A start of frame is 7E 00 not only 7E. Make sure the first read sequence is
starting with 7E 00.
For example: 7E FF FF FF FF is as a correct crc but it is a bad frame.
Signed-off-by: NChristophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>