ti: k3: drivers: sec_proxy: Fix printf format specifiers

The ID of a thread is not used outside for printing it out when
something goes wrong. The specifier used is also not consistent.
Instead of storing the thread ID, store its name and print that.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Change-Id: Id137c2f8dfdd5c599e220193344ece903f80af7b