Revert "tracing: Check "%s" dereference via the field and not the TP_printk format"

This reverts commit f452f397 which is
commit afd2627f upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I1738e91c7ebd042d11a58719318127dc4ec6fc23
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>