exynos: multimedia: speed up color conversion from ARGB8888 to YUV420SP

Use NEON instructions for color conversion from ARGB8888 to YUV420SP. This
greatly improves performance and can help achieve 30fps+ framerates when
dealing with OMX_COLOR_FormatAndroidOpaque during Screen Recording and
Screen Casting.

Change-Id: Ifdaaf03e1ce6909822df3f046ef35dd977b84d17
4 files changed