minigbm: align first plane to 64 bytes

The chroma stride of Android YV12 buffers is required to be
aligned to 16 bytes (see <system/graphics.h>).

Additionally, the size of the ARM L1 cache line is 64-bytes
(see chrome-os-partner:45777).

Let's always align the first plane to 64 bytes. The chroma strides
will be aligned to 32 bytes in that case.

BUG=chromium:616275
TEST=

ImageReaderDecoderTest#testGoogH264ImageReader

passes on veyron_minnie-cheets.

Change-Id: I87a309ce0612bf8c5be8f8e47dad3da10d61a081
Reviewed-on: https://chromium-review.googlesource.com/441912
Commit-Ready: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
2 files changed