regmap: Fix apostrophe usage

An apostrophe does not mean "look out, here comes an s!".

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 4dfab41..2caf6e4 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -118,7 +118,7 @@
 			return -ENOMEM;
 		map->reg_defaults = tmp_buf;
 	} else {
-		/* Some devices such as PMIC's don't have cache defaults,
+		/* Some devices such as PMICs don't have cache defaults,
 		 * we cope with this by reading back the HW registers and
 		 * crafting the cache defaults by hand.
 		 */