Fix overlap of inet keys with jp Henkan and Muhenkan keys

Fix overlap of inet keys with jp Henkan and Muhenkan keys

The keyboard driver (for legacy keyboards) reports the same
keycodes for some inet keys as for the extra keys (Henkan and
Muhenkan) on Japanese 106 keyboards.
So on these keyboards Japanese users either loose their extra
keys or some multimedia keys.
In:

commit bd9d0ced6154de583c96573585f428618017fca3

    Fix henkan key on jp106 keyboard with inet media keys

the Henkan/Muhenkan keys were reintroduced.
A better fix will map one of the two sets to different and still
unused keycodes.
A patch for the xf86-input-keyboard driver moves the two inet keys
into the range above 0xfb.
This patch contains the corresponding changes to xkeyboard-config.
Both the legacy keyboard driver and xkeyboard-config will have to
be updated simultaniously otherwise users will loose the two affected
multmedia keys.

Signed-off-by: Egbert Eich <eich@freedesktop.org>