msm: mdss: abstract the dsi command utility API

The dsi command parsing and construction functionalities
are hardware independent.  This is to abstract these
utility API, so that it can be shared with different versions
of  dsi host controllers.

Change-Id: I8481d9fd21e5eacc4542c72c064fa37d7fd3a11b
Signed-off-by: Xiaoming Zhou <zhoux@codeaurora.org>
msm: mdss: Add an extra write of zero to clear dsi-ack-err bit

In addition to writing 1 to clear dsi-ack-err bit, an extra write
of 0 is also needed to clear error bit completely.

CRs-fixed: 574066
Change-Id: Ib9df9fe5f993605372ced8766874fa00538f505a
Signed-off-by: Shivaraj Shetty <shivaraj@codeaurora.org>