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: I1c41256ffbc30abcf9f7b0b5fcf53da40462da28
1 file changed