Please apply 2c155709e4ef ("staging: android: ion: fix ION_IOC_{MAP,SHARE} use-after-free") to 3.18.y

[Greg Hackmann <ghackmann@xxxxxxxxxx>]

2c155709e4ef ("staging: android: ion: fix ION_IOC_{MAP,SHARE} 
use-after-free") was applied to 4.4.y a couple of weeks ago, and is 
needed on 3.18.y too.  The patch cherry-picks and builds as-is on top of 
3.18.123.