glsl/parser: Allocate identifier inside classify_identifier

glsl/parser: Allocate identifier inside classify_identifier

Passing YYSTYPE into classify_identifier enables a later patch.

   text	   data	    bss	    dec	    hex	filename
8310339	 269336	 294072	8873747	 876713	32-bit i965_dri.so before
8275163	 269336	 294072	8838571	 86ddab	32-bit i965_dri.so after
7845579	 346552	 420592	8612723	 836b73	64-bit i965_dri.so before
7836963	 346552	 420592	8604107	 8349cb	64-bit i965_dri.so after

Yes, the 64-bit binary shrinks by 8k.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>