glapi/glx: Mark the indirect swapped dispatch functions _X_COLD

A modest size savings:

   text	   data	    bss	    dec	    hex	filename
 264143	  15608	    232	 279983	  445af libglx.so.before
 254303	  15608	    232	 270143	  41f3f libglx.so.after

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Adam Jackson <ajax@redhat.com>
1 file changed