exFAT fs driver has been upstreamed as a staging driver since linux 5.4.
The package name kmod-fs-exfat is used for that.

Three things happened in this commit

 - The package will only be built for kernel 4.14 and 4.19
 - The driver will be available as opkg package "kmod-fs-exfat0".
   "kmod-fs-exfat" is to be used for the one in upstream kernel
 - Mark "kmod-fs-exfat0" as deprecated in package title

Signed-off-by: Paul Blazejowski <paulb at blazebox.homeip.net>
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>
(rename, rewording, and deprecation)