regulator: Remove pointer table overallocation

The code allocates sizeof(regulator_dev) for a pointer. Make it less
generous. Let kcalloc() calculate the size, while at it.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/407fbd06a02caf038a9ba3baa51c7d6d47cd6517.1597000795.git.mirq-linux@rere.qmqm.plSigned-off-by: NMark Brown <broonie@kernel.org>

drivers/regulator/core.c

@@ -5030,20 +5030,20 @@ static void regulator_remove_coupling(struct regulator_dev *rdev)
 
 static int regulator_init_coupling(struct regulator_dev *rdev)
 {
+	struct regulator_dev **coupled;
 	int err, n_phandles;
-	size_t alloc_size;
 
 	if (!IS_ENABLED(CONFIG_OF))
 		n_phandles = 0;
 	else
 		n_phandles = of_get_n_coupled(rdev);
 
-	alloc_size = sizeof(*rdev) * (n_phandles + 1);
-
-	rdev->coupling_desc.coupled_rdevs = kzalloc(alloc_size, GFP_KERNEL);
-	if (!rdev->coupling_desc.coupled_rdevs)
+	coupled = kcalloc(n_phandles + 1, sizeof(*coupled), GFP_KERNEL);
+	if (!coupled)
 		return -ENOMEM;
 
+	rdev->coupling_desc.coupled_rdevs = coupled;
+
 	/*
 	 * Every regulator should always have coupling descriptor filled with
 	 * at least pointer to itself.