msm_fb: display: replace cmds_tx/rx with cmdlist_put/get

Both dcs command and mdp pixel stream share dsi link. Dsi link
confliction may cause mdp to hang up. cmdlist mechanism is
introduced to serialize both dcs commands and mdp pixel stream.
This patch replaces legacy cmds_tx/rx with cmdlist_put/get.

add to LGIT

Change-Id: I03746af6e094f44af624fae62a2319963d077f55