mesa: replace for loop with bitshifting in supported_buffer_bitmask()
mesa: replace for loop with bitshifting in supported_buffer_bitmask()

Reviewed-by: Rob Clark <915c10c999604870200b6defbe633d857c856ca0@gmail.com>
Reviewed-by: Roland Scheidegger <7d58aee419d6f9201d75517c885374dff5e7d848@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler