Fix RS test apk problems

1). Fix RS sample display
Multiply rsSample outputs with 255.0f, or else no display for RS sample

2). Fix RS sample no display
Set Allocation.USAGE_GRAPHICS_TEXTURE when preparing RS Allocation,
or else rsSample() returns 0 which causes no display for RS sample.

Change-Id: Ifb52b0862f448b611fbdca1633d3118427ed415a
Signed-off-by: Xiaofei Wan <xiaofei.wan@intel.com>
2 files changed