mfd: core: Fix double-free in mfd_remove_devices_fn()

The pdev.mfd_cell is released by platform_device_release(), which is
invoked by platform_device_unregister(). Hence mfd_remove_devices_fn()
shouldn't release the cell variable. The double-free bug is reported KASAN
during of MFD driver module removal.

Fixes: 466a62d7 ("mfd: core: Make a best effort attempt to match devices with the correct of_nodes")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/mfd-core.c

@@ -370,8 +370,6 @@ static int mfd_remove_devices_fn(struct device *dev, void *data)
 	regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies,
 					       cell->num_parent_supplies);
 
-	kfree(cell);
-
 	platform_device_unregister(pdev);
 	return 0;
 }