vpp: use new interface to increase accuracy of ar calculation [1/2]

vpp: use new interface to increase accuracy of ar calculation [1/2]

PD#OTT-2068

Problem:
When playing 1280x128 video under normal screen mode, the aspect ratio from
decodec is not accurate enough by multipling 0x100. (128x256/1280=25.6).
Dropping 0.6 will cause height losing 9 lines.

Solution:
Using new interface to pass real ar width and height following steps:
1.Set old ar variable to 0x3ff as a trigger flag.
2.set the original ar value into sar_width and sar_height of vframe

Verify:
verified on franklin

Change-Id: I8a794edd968a76f198ee9cb168a7cfb858c858f8
Signed-off-by: Brian Zhu <brian.zhu@amlogic.com>