trace: remove some unused trace_dump_tag*() functions

trace: remove some unused trace_dump_tag*() functions

Fixes the following Clang warnings.

tr_dump.c:137:1: warning: unused function 'trace_dump_tag' [-Wunused-function]
trace_dump_tag(const char *name)
^
tr_dump.c:168:1: warning: unused function 'trace_dump_tag_begin2' [-Wunused-function]
trace_dump_tag_begin2(const char *name,
^
tr_dump.c:187:1: warning: unused function 'trace_dump_tag_begin3' [-Wunused-function]
trace_dump_tag_begin3(const char *name,
^
  CC       tr_texture.lo
3 warnings generated.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>