msm_fb: display: adjust refx100 parameter to avoid tearing

refx100 is used to calculate how many mdp_vsync clocks to complete one
line in the panel. This info is used by mdp h/w to sync data transfer
between mdp h/w and command mode panel to avoid tearing.

CRs-fixed: 379223
Change-Id: I3880a350b77cb8165745ea343b1525e84100a62d
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>