regulator: tps51632: convert to use maple tree register cache

The maple tree register cache is based on a much more modern data structure
than the rbtree cache and makes optimisation choices which are probably
more appropriate for modern systems than those made by the rbtree cache.

Signed-off-by: Bo Liu <[e-mail]>
Link: https://msgid.link/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/tps51632-regulator.c

···
 	.readable_reg		= is_read_reg,
 	.volatile_reg		= is_volatile_reg,
 	.max_register		= TPS51632_MAX_REG - 1,
-	.cache_type		= REGCACHE_RBTREE,
+	.cache_type		= REGCACHE_MAPLE,
 };
 
 #if defined(CONFIG_OF)