Fixed SystemUI crash when disable GPU acceleration

The designated logic should switch to SW Canvas render if OpenGL-ES 2.0
is not available when GPU 3D core is disabled or non-existed.

Change-Id: Ie66799bc9e1113a4b09adbb09b77021622a08bc4
Signed-off-by: Xianzhong <b07117@freescale.com>
Signed-off-by: guoyin.chen <guoyin.chen@freescale.com>