mesa: remove some unused functions in the perf monitor area
mesa: remove some unused functions in the perf monitor area

Fixes the following Clang warnings.

main/performance_monitor.c:157:1: warning: unused function 'index_to_queryid' [-Wunused-function]
index_to_queryid(GLuint index)
^
main/performance_monitor.c:163:1: warning: unused function 'queryid_valid' [-Wunused-function]
queryid_valid(const struct gl_context *ctx, GLuint queryid)
^
main/performance_monitor.c:169:1: warning: unused function 'counterid_to_index' [-Wunused-function]
counterid_to_index(GLuint counterid)
^
3 warnings generated.

Signed-off-by: Samuel Pitoiset <506e97eed81d9e59d22f4c73fb51123bb62b4a30@gmail.com>
Reviewed-by: Brian Paul <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler