staging: android/ion: Don't use return in void function

Return statements are superfluous in void functions, and checkpatch
complains about them too.

Remove offending return.

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>