Recovery mode UI flicker

[root cause  ] miniui has no mechanism to protect
               the buffer which is displaying
[changes     ] recovery
[side effects] ui show
[self test   ] sc9850-2 general operation has not display abnormal
[reviewers   ] xinglong.zhu

Signed-off-by: xinglong.zhu <xinglong.zhu@spreadtrum.com>
[change_type ] AOB --> google_original
[tag_product ] common

Change-Id: I989a0b2943ff6070a0e98718cfbe95144510d3a2