mm/damon/core: remove per-scheme region priority histogram buffer

Nobody is reading from or writing to the per-scheme region priorities
histogram buffer.  It is only wasting memory.  Remove it.

Link: https://lkml.kernel.org/r/20240826042323.87025-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/damon.h

@@ -233,7 +233,6 @@ struct damos_quota {
 	unsigned long charge_addr_from;
 
 	/* For prioritization */
-	unsigned long histogram[DAMOS_MAX_SCORE + 1];
 	unsigned int min_score;
 
 	/* For feedback loop */