radeonsi: make pm4 state generation for shaders independent of the context
radeonsi: make pm4 state generation for shaders independent of the context

The si_pm4_delete_state calls became useless, because the pm4 state is
always generated only once.

Reviewed-by: Michel Dänzer <242b79f0804cf52679d58f27ed754158c1323c75@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler