regmap: Use mas_walk() instead of mas_find()

Liam recommends using mas_walk() instead of mas_find() for our use case so
let's do that, it avoids some minor overhead associated with being able to
restart the operation which we don't need since we do a simple search.
Suggested-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230403-regmap-maple-walk-fine-v2-1-c07371c8a867@kernel.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regcache-maple.c

@@ -22,7 +22,7 @@ static int regcache_maple_read(struct regmap *map,
 
 	rcu_read_lock();
 
-	entry = mas_find(&mas, reg);
+	entry = mas_walk(&mas);
 	if (!entry) {
 		rcu_read_unlock();
 		return -ENOENT;
@@ -47,7 +47,7 @@ static int regcache_maple_write(struct regmap *map, unsigned int reg,
 
 	rcu_read_lock();
 
-	entry = mas_find(&mas, reg);
+	entry = mas_walk(&mas);
 	if (entry) {
 		entry[reg - mas.index] = val;
 		rcu_read_unlock();