opal_setup_cc.m4: remove dead code

We haven't supported AIX in years.

Signed-off-by: Jeff Squyres <jsquyres@cisco.com>
(cherry picked from commit a086a5c)

Author: jsquyres

config/opal_setup_cc.m4

@@ -411,10 +411,6 @@ AC_DEFUN([OPAL_SETUP_CC],[
 
 AC_DEFUN([_OPAL_START_SETUP_CC],[
     opal_show_subtitle "C compiler and preprocessor"
-
-	# $%@#!@#% AIX!!  This has to be called before anything invokes the C
-    # compiler.
-    dnl AC_AIX
 ])