FileSystemPermissionTest: Whitelist kgsl 2d char devices

Cherrypicked from https://android-review.googlesource.com/67660

Adding two exceptions which are needed by some devices
/dev/kgsl-2d0 and /dev/kgsl-2d1

kgsl-2d0 and kgsl-2d1 devices are 2D acceleration H/W
that is used by HWC, Camera and Media server. Also 2D
acceleration APIs are published to OEM's to develop apps.
All 2d dependent apps (directly using 2d APIs) need "666"
permission to make use of H/W acceleration.

Current kgsl implementation on 8960 MR2 is to only allow
access to memory visible and accessible by the user
process that opens the kgsl driver. The process can't
access arbitrary physical memory by passing a physical
memory address. kgsl driver will reject such a request.

The kgsl driver only access to memory region which is own
by same process. It can't access other process memory and
cause security issue.

Bug: 11271533
Bug: 11680659

Change-Id: Ic6c77d4eb8348e416220c23aaf0201306d798816
(cherry picked from commit 5a04d9c2)