sde: Set the recommended rotator output format for NV21

NV21 as rotator output has not undergone intensive H/W validation.
In order to avoid possible corner case issues, it is recommended
to use NV12 as rotator output format, if the input format is NV21.

Change-Id: I8eff6a5ec15c6170e1393443f0bf242832b949cc
1 file changed