remove x86_64 comments from arch specific Config

options are in main makefile now

src/arch/i386/Config

 
 # An alternate location for isolinux.bin can be set here
 # ISOLINUX_BIN=/path/to/isolinux.bin
-
-# These seem to have some relevance to compiling on x86_64
-# EXTRA_CFLAGS=-m32
-# EXTRA_ASFLAGS=--32
-# EXTRA_LDFLAGS=-m elf_i386