kernel: remove left-over code from object monitoring

This code is non-functional and is a left over from an old version of
the kernel that does not work and is covered through other new features
in the kernel, for example object tracing.

Jira: ZEP-2013
Change-Id: Id12ad09e2d06186b53cd2f0dd030ac6d37d1229f
Signed-off-by: Anas Nashif <anas.nashif@intel.com>