staging: android: ion: Merge ion-ioctl.c into ion.c

The file ion-ioctl.c is now much to small and tightly integrated
with the main ion.c file to justify keeping it separate. Merge
this file.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>