Move cursor programming to inside the OTG_MASTER_UPDATE_LOCK

If graphics plane go from 1 pipe to hsplit, the cursor updates
after mpc programming and unlock. Which means there is a window
of time where cursor is enabled on the wrong pipe if it's on
the right side of the screen (i.e. case where cursor need to
move from pipe 0 to pipe 3 post split). This will cause pstate hang.

Solution is to program the cursor while still locked.
Signed-off-by: Eric Yang <Eric.Yang2@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>