msm: mdss: Fix rgb_565 format for 90 degree rotation

Make rotator output format for rgb_565 and bgr_565
as rgb_888 for 90 degree rotation as expected by
MDSS.

Change-Id: I0865b5688fa662d1e88d1efebef26a38d4abfd61
Signed-off-by: Pawan Kumar <pavaku@codeaurora.org>