Fix a minor bug in banned API check script

Avoid false positives due to partial match of new APIs with the
banned libc APIs.

Ex: A patch which introduced support for strtok_r() failed static
checks because of match with strtok() banned API

Also updated the coverity exclusion file as no platform uses the
libc strtok_r function.

Change-Id: I59ed31ac952d152561fd75e8c928057780503976
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
2 files changed