UPSTREAM: mm/damon/core: print kdamond start log in debug mode only

Logging of kdamond startup is using 'pr_info()' unnecessarily.  This
makes it to use 'pr_debug()' instead.

Link: https://lkml.kernel.org/r/20210917123958.3819-6-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

(cherry picked from commit 704571f9)

Bug: 228223814
Signed-off-by: Hailong Tu <tuhailong@oppo.com>
Change-Id: Idf59dd43a8cecfbbe2846bfa81a8c79744ce08c9