rs6000: Remove old "Cygnus sibcall" comment

This comment is quite cryptic and very out-of-date by now.  Committing.


	* config/rs6000/rs6000.md: Remove old "Cygnus sibcall" comment.

From-SVN: r264403

gcc/ChangeLog

 2018-09-18  Segher Boessenkool  <segher@kernel.crashing.org>
 
+	* config/rs6000/rs6000.md: Remove old "Cygnus sibcall" comment.
+
+2018-09-18  Segher Boessenkool  <segher@kernel.crashing.org>
+
 	PR rtl-optimization/86882
 	* rtlanal.c (reg_overlap_mentioned_p): Handle CLOBBER.
 

gcc/config/rs6000/rs6000.md

@@ -13062,8 +13062,7 @@
    (set_attr "indexed" "yes")
    (set_attr "cell_micro" "always")])
 
-; FIXME: This would probably be somewhat simpler if the Cygnus sibcall
-; stuff was in GCC.  Oh, and "any_parallel_operand" is a bit flexible...
+; FIXME: "any_parallel_operand" is a bit flexible...
 
 ; The following comment applies to:
 ;     save_gpregs_*