gpu: ion: Get an sg_table from an ion handle

This patch adds an interface to return and sg_table given a
valid ion handle.

Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/staging/android/ion/ion.c
Simple merge

diff --cc drivers/staging/android/ion/ion.h
Simple merge