Put HAL_PIXEL_FORMAT_RGB_888 back for CPU access

BasicVulkanGpuTest expilictly requests
GPU_SAMPLED_IMAGE usage, we can use it to decide
if we support RGB_888 (Vulkan does not support it).
HardwareBufferTest#testCreate requests only CPU access.

Bug: 132447509
Bug: 131184223
Test: [OpenGL, Vulkan] x [CtsGraphicsTestCases, CtsHardwareTestCases]
Change-Id: I2bbcddd2b3153208cbb00b76caca9564b743c61e
Merged-In: Ib3f5d6cd9ed361205952d99b2f7173d5518dea79
Signed-off-by: Roman Kiryanov <rkir@google.com>