BufferQueue: Increase max slots from 32 to 64

Increases NUM_BUFFER_SLOTS from 32 to 64 and changes the mask
returned by IGBC::getReleasedBuffers from 32 to 64 bits.

Bug: 13174352
Change-Id: Ie8ef0853916cfb91f83881c7241886bb1950f01a
10 files changed