msm: mdss: Acquire shared lock after getting frame on wfd

Currently there is a deadlock when wfd and rotation is done
simultaneously and trying to acquire the shared lock. To
prevent this, acquire shared lock after rotated frame is
ready for wfd.

Change-Id: I3865f02c345ddadd985ee35134454a789936a79a
Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>