libvideorender: CF2 add set display rate feature [1/1]

PD#SWPL-172524

Problem:
set frame rate to weston, weston will select drm mode by
frame rate.

Solution:
1.add set display rate feature
2.set default 59.94 fps to weston if frame rate is
invalid

Verify:
ap222

Change-Id: Ie0ed78eb3e747776b3905e3276801b3f3d01b44f
Signed-off-by: fei.deng <fei.deng@amlogic.com>
5 files changed