CCodec: fix not to use YV12 format on COLOR_FormatYUV420Flexible for pre-S

COLOR_FormatYUV420Flexible has been mapped to
HAL_PIXEL_FORMAT_YCBCR_420_888 at pre-S devices since android R.
for backward compatibility, it should be handled by
HAL_PIXEL_FORMAT_YCBCR_420_888.

Bug: 248144271

Signed-off-by: Taehwan Kim <t_h.kim@samsung.com>
Change-Id: I8acdd105c6fe90403bc83bc567736652e838df43