samples/damon/prcl: avoid starting DAMON before initialization

Commit 2780505e ("samples/damon/prcl: fix boot time enable crash") is
somehow incompletely applying the origin patch [1].  It is missing the
part that avoids starting DAMON before module initialization.  Probably a
mistake during a merge has happened.  Fix it by applying the missed part
again.

Link: https://lkml.kernel.org/r/20250909022238.2989-3-sj@kernel.org
Link: https://lore.kernel.org/20250706193207.39810-3-sj@kernel.org

 [1]
Fixes: 2780505e ("samples/damon/prcl: fix boot time enable crash")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>