UPSTREAM: mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log

The failure log message for 'damon_va_three_regions()' prints the target
id, which is a 'struct pid' pointer in the case.  To avoid exposing the
kernel pointer via the log, this makes the log to use the index of the
target in the context's targets list instead.

Link: https://lkml.kernel.org/r/20211229131016.23641-4-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

(cherry picked from commit 962fe7a6)

Bug: 228223814
Signed-off-by: Hailong Tu <tuhailong@oppo.com>
Change-Id: I6b9b09a9b7024630f05ec41db030006d63f47ce1