"drivers/staging: mark android/ion fcns with EXPORT_SYMBOL for tristate

In a recent change, we made a bool into a tristate in:
"drivers/staging: make android tegra_ion.c properly tristate", since it
was self evident that was the original intention.  However on the final
link phase we'll see an allmodconfig fail with:

ERROR: "ion_device_add_heap" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_heap_create" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_device_create" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_heap_destroy" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_device_destroy" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!

Export the above using the non GPL specific export, since that is what
the rest of the ion code base does.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Markus Elfring <elfring@users.sourceforge.net>
Cc: devel@driverdev.osuosl.org
Cc: linux-tegra@vger.kernel.org
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion.c

@@ -1557,6 +1557,7 @@ void ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap)
 
 	up_write(&dev->lock);
 }
+EXPORT_SYMBOL(ion_device_add_heap);
 
 struct ion_device *ion_device_create(long (*custom_ioctl)
 				     (struct ion_client *client,
@@ -1606,6 +1607,7 @@ struct ion_device *ion_device_create(long (*custom_ioctl)
 	idev->clients = RB_ROOT;
 	return idev;
 }
+EXPORT_SYMBOL(ion_device_create);
 
 void ion_device_destroy(struct ion_device *dev)
 {
@@ -1614,6 +1616,7 @@ void ion_device_destroy(struct ion_device *dev)
 	/* XXX need to free the heaps and clients ? */
 	kfree(dev);
 }
+EXPORT_SYMBOL(ion_device_destroy);
 
 void __init ion_reserve(struct ion_platform_data *data)
 {

drivers/staging/android/ion/ion_heap.c

@@ -352,6 +352,7 @@ struct ion_heap *ion_heap_create(struct ion_platform_heap *heap_data)
 	heap->id = heap_data->id;
 	return heap;
 }
+EXPORT_SYMBOL(ion_heap_create);
 
 void ion_heap_destroy(struct ion_heap *heap)
 {
@@ -379,3 +380,4 @@ void ion_heap_destroy(struct ion_heap *heap)
 		       heap->type);
 	}
 }
+EXPORT_SYMBOL(ion_heap_destroy);