exports.h: bump XF_VERSION

exports.h: bump XF_VERSION

There have been quite a few changes to _exports.h since the last
update of XF_VERSION, also before the previous patches in this series.

I doubt the mechanism is actually being used in practice, it is simply
too fragile: Not only does the list of exported functions depend on
.config, so with the same XF_VERSION the jump table entries could have
different offsets. But getting to the jump table itself from gd to
even call the ->get_version() is fragile, since offsetof(gd_t, jt)
can, and does, change. For example, as recently as commit
d9902107027 ("global_data: Remove jump table in SPL").

One really must build one's standalone app against the proper U-Boot
version and config.h. But for good measure, do bump it now.

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
Reviewed-by: Tom Rini <trini@konsulko.com>