mfd: twl6040: Use maple tree register cache

The twl6040 is only capable of performing single register read and write
operations which means it gains no advantage from using a rbtree register
cache, convert it to using the more modern maple tree register cache
instead. This should be more efficient.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230609-mfd-twl6040-maple-v1-1-3493d051cd6f@kernel.orgSigned-off-by: Lee Jones <lee@kernel.org>

drivers/mfd/twl6040.c

@@ -608,7 +608,7 @@ static const struct regmap_config twl6040_regmap_config = {
 	.volatile_reg = twl6040_volatile_reg,
 	.writeable_reg = twl6040_writeable_reg,
 
-	.cache_type = REGCACHE_RBTREE,
+	.cache_type = REGCACHE_MAPLE,
 	.use_single_read = true,
 	.use_single_write = true,
 };