st/mesa: Set EmitNoIndirectSampler if GLSLVersion < 400.

st/mesa: Set EmitNoIndirectSampler if GLSLVersion < 400.

This patch changes the code which sets EmitNoIndirectSampler to check
the core profile GLSL version, rather than the ARB_gpu_shader5 extension
enable.  st/mesa exposes ARB_gpu_shader5 if GLSLVersion (in core
profiles) or GLSLVersionCompat (in compat profiles) >= 400.

The Intel drivers do not currently expose ARB_gpu_shader5 in compat
profiles.  But the backend can absolutely handle indirect samplers.
Looking at the core profile version number should be a good indication
of what the driver supports.

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>