stagefright: ifdef "libstagefright: Use proper ctts offset"

Causes A/V sync issues or corrupted recordings on NON-QCOM hardware

Change-Id: I8c8625c41936c3ecc9a70f82ddc17e6e66503fd3
stagefright: fix YV12 chroma stride align for Exynos4

Commit 906eba (exynos4: libstragefright: add support for samsung colorformat/omx/mfc)
was supposed to apply YV12 chroma stride align to 16 for the Planar format but was
mistakenly applied for all the other formats.

Source: http://git.insignal.co.kr/samsung/exynos/android/platform/frameworks/base/tree/media/libstagefright/colorconversion/SoftwareRenderer.cpp?h=exynos-ics&id=ede5597dcf8e9626b6a0ecf1a025c1e4bf57411e#n161

Change-Id: Iae0e785a908be8a452f6c5e947cd0175d777165b
stagefright: Add flag for enabling enhanced offload support

 * Some devices might not use the QCOM_HARDWARE flag, but still
   want to get the improved audio offload support.
 * Add TARGET_ENABLE_OFFLOAD_ENHANCEMENTS to enable support for
   PCM offload and 24-bit playback with no extra dependencies.

Change-Id: Ie1a92602c6c0cd59008db8dbf72125eecef08e85