msm: mdss: fix misr offsets for 8996 cmd mode

Set the correct offsets of the MISR for command mode
interfaces in 8996.

CRs-Fixed: 964076
Change-Id: I90c7fa1ff144ae547cc0537421211a73051f1036
Signed-off-by: Ingrid Gallardo <ingridg@codeaurora.org>