scripts/addToolsVersion: handle elf2flt

The one was missing from the list.

It is very improbable that we ever need it, as elf2flt does no release,
and we always get it from CVS head. But for the sake of consistency, we
just add it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 # windows config options

 ## depends on ARCH_x86

 ##

 ## select WINDOWS

 ##

 ## help Build a toolchain targeting systems running Windows as host