Fix CacheBitmap crash issue when using H/W UI rendering

Avoid to access invalid index in CacheBitmap. That will cause the android SDK image cannot be booted up
with H/W GL enabling. This patch is required by both ARM and x86 SDK system image.

Change-Id: I705b7f06915a2338a2f94509486344bfd92b4bfb
Signed-off-by: Jun Tian <jun.j.tian@intel.com>
Signed-off-by: Jackie Wu <jackie.wu@intel.com>
Signed-off-by: Liang Chen <liang.l.chen@intel.com>
Signed-off-by: Panfeng Chang <panfengx.chang@intel.com>