i965: fix projtex_mask

projtex_mask is only an 8bit field, and wm.input_size_masks includes
other attributes' information, therefore right shift is needed.

src/mesa/drivers/dri/i965/brw_wm.c

@@ -285,7 +285,7 @@ static void brw_wm_populate_key( struct brw_context *brw,
 
 
    /* BRW_NEW_WM_INPUT_DIMENSIONS */
-   key->projtex_mask = brw->wm.input_size_masks[4-1]; 
+   key->projtex_mask = brw->wm.input_size_masks[4-1] >> (FRAG_ATTRIB_TEX0 - FRAG_ATTRIB_WPOS); 
 
    /* _NEW_LIGHT */
    key->flat_shade = (brw->attribs.Light->ShadeModel == GL_FLAT);

src/mesa/drivers/dri/i965/brw_wm_fp.c

@@ -660,7 +660,7 @@ static GLboolean projtex( struct brw_wm_compile *c,
       return 0;  /* ut2004 gun rendering !?! */
    else if (src.File == PROGRAM_INPUT && 
 	    GET_SWZ(src.Swizzle, W) == W &&
-	    (c->key.projtex_mask & (1<<src.Index)) == 0)
+           (c->key.projtex_mask & (1<<(src.Index + FRAG_ATTRIB_WPOS - FRAG_ATTRIB_TEX0))) == 0)
       return 0;
    else
       return 1;