assembler/skl: update read(...)
assembler/skl: update read(...)

READ(...) is used for Render Target read and Media Block read. But there is no
sampler cache agent on gen9. At the same time two message types don't
share the same cache agent any more. So a parameter is needed for cache agent.
The 2th parameter of read(...) is not used for gen6/gen7/gen8. Hence it is
reused as cache agent for SKL as that on ILK.

Signed-off-by: Zhao Yakui <21bae65ecea50a19bd9d0fef489914760189fd5b@intel.com>
Signed-off-by: Ben Widawsky <cf148a1c890adeeb4308e9e093ed95f3d05c8318@intel.com>
Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@intel.com>

dlespiau/checkmate-test-igt,dlespiau/checkmate-test-igt,chenxianqin/intel-gpu-tools,erikarn/intel-gpu-tools,tiagovignatti/intel-gpu-tools,tiagovignatti/intel-gpu-tools,mv0/intel-gpu-tools,tiagovignatti/intel-gpu-tools,yipdw/intel-gpu-tools,chenxianqin/intel-gpu-tools,yipdw/intel-gpu-tools,chenxianqin/intel-gpu-tools,mv0/intel-gpu-tools,mv0/intel-gpu-tools,erikarn/intel-gpu-tools,mv0/intel-gpu-tools,erikarn/intel-gpu-tools,yipdw/intel-gpu-tools,yipdw/intel-gpu-tools,tiagovignatti/intel-gpu-tools,erikarn/intel-gpu-tools,dlespiau/checkmate-test-igt,dlespiau/checkmate-test-igt,chenxianqin/intel-gpu-tools