ima: Rename internal filter rule functions

[ Upstream commit b8867eed ]

Rename IMA's internal filter rule functions from security_filter_rule_*()
to ima_filter_rule_*(). This avoids polluting the security_* namespace,
which is typically reserved for general security subsystem
infrastructure.

Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Suggested-by: Casey Schaufler <casey@schaufler-ca.com>
[zohar@linux.ibm.com: reword using the term "filter", not "audit"]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Stable-dep-of: c7423dbd ("ima: Handle -ESTALE returned by ima_filter_rule_match()")
Signed-off-by: Sasha Levin <sashal@kernel.org>