regulator: Remove NULL test before calling regulator_unregister()

It's safe to call regulator_unregister() with NULL, thus remove the NULL test
before regulator_unregister() calls.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@sirena.org.uk>
diff --git a/drivers/regulator/max1586.c b/drivers/regulator/max1586.c
index 8c5a54f..6b2217b4 100644
--- a/drivers/regulator/max1586.c
+++ b/drivers/regulator/max1586.c
@@ -232,8 +232,7 @@
 	int i;
 
 	for (i = 0; i <= MAX1586_V6; i++)
-		if (max1586->rdev[i])
-			regulator_unregister(max1586->rdev[i]);
+		regulator_unregister(max1586->rdev[i]);
 	return 0;
 }