Add usage flags for old gralloc
Add usage flags for old gralloc

vkgetSwapchainGrallocUsageANDROID() now sets
a single flag to GRALLOC_USAGE_SW_WRITE_OFTEN

Bug: b/122837237
Change-Id: I809659c6bbc49b84302b8c58751de5ed0135b1ef
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/32249
Tested-by: Hernan Liatis <aae823fecbd46cfee57ca49420b0f7c28a5fd12e@google.com>
Kokoro-Presubmit: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader