[syslinux] Updated status on UEFI compliant version of the pxechn-module

[Ady]

>  EFI access from Com32 modules 
>  http://www.syslinux.org/archives/2015-March/023320.html 
 
Developers,

I beg you, please limit the file names to 8.3 whenever possible. If 
there is no essential need for a file name to be non-compliant with 
"8.3", then please, make us all a favor and use "8.3".

Reasoning:

ISO9660 Level1 and FAT without LFN only understand "8.3", so for file 
names to be easily portable between filesystems, it is recommended to 
use "8.3" whenever possible.

This is even more relevant for bootloader files, for C32 modules, and 
for kernel / initrd / other boot-related files.

Thank you,
Ady.