i965: Remove default from brw_instruction_name switch to catch missing names.
i965: Remove default from brw_instruction_name switch to catch missing names.

The case-range extension is available in clang and gcc at least back to
3.4.0.

Signed-off-by: Chris Forbes <5dcac483e7a6e31a5cbe89f38cc69dff8ee93dac@ijw.co.nz>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler