qcedev: fix UAF in qcedev_smmu

External researcher found UAF in qcedev_smmu.c on an error condition in
qcedev_check_and_map_buffer. When an error occurs, we free binfo, but it
is still kept in the registeredbufs list. The fix removes it from the
list before freeing binfo.

Change-Id: I0327e456bd46106b12c36a5a21305407aae428dd
Signed-off-by: Daniel Perez-Zoghbi <quic_dperezzo@quicinc.com>