[gfxstream] Small optimization on transformDescriptorSetList

Reduce number of possible allocations and remove unnecessary
memory initialization which will be overwritten immediately.

Bug: 406456167
Test: dEQP-GLES31.functional.ssbo.layout.*
Change-Id: I47b518a0a6a3952f16a47104fa0b7fceaf66caa1
1 file changed