msm: ipa: fix to NULL terminate the pointer

Fix to NULL terminate the peers list ptr
after freeing it, to get rid of use after
free issue.

Change-Id: Ide9fde9e7648a7af561a5b0ae0fa085810e59ea6
Signed-off-by: Prashanth Reddy Baddam <quic_pbaddam@quicinc.com>