mfd-core: Unconditionally add mfd_cell to every platform_device

Previously, one would set the mfd_cell's platform_data/data_size to point
to the current mfd_cell in order to pass that information along to drivers.

This causes the current mfd_cell to always be available to drivers.  It
also adds a wrapper function for fetching the mfd cell from a platform
device, similar to what originally existed for mfd devices.

Drivers who previously used platform_data for other purposes can still
use it; the difference is that mfd_get_data() must be used to
access it (and the pdata structure is no longer allocated in
mfd_add_devices).

Note that mfd_get_data is intentionally vague (in name) about where
the data is stored; variable name changes can come later without having
to touch brazillions of drivers.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index d83ad0f..21a39dc 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -39,12 +39,9 @@
 	pdev->dev.parent = parent;
 	platform_set_drvdata(pdev, cell->driver_data);
 
-	if (cell->data_size) {
-		ret = platform_device_add_data(pdev,
-					cell->platform_data, cell->data_size);
-		if (ret)
-			goto fail_res;
-	}
+	ret = platform_device_add_data(pdev, cell, sizeof(*cell));
+	if (ret)
+		goto fail_res;
 
 	for (r = 0; r < cell->num_resources; r++) {
 		res[r].name = cell->resources[r].name;