msm_fb: display: free borderfill pipe when ref_cnt reach 0

Borderfill pipe need to be kept as baselayer which is not
suppose to be freed at suspend. It only be freed when
ref_cnt reach 0 by "adb stop".

CRs-fixed: 429196
Change-Id: Ibffe7960cc194162d1ba71e8dc8636393938483f
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>