keycodes: ignore explicit minimum/maximum statements

keycodes: ignore explicit minimum/maximum statements

These statements are pretty pointless for us; we don't restrict keycodes
like X does, and if someone writes e.g. maximum = 255 but only has 100
keys, we currently happily alloc all those empty keys. xkbcomp already
handles the case when these statements aren't given, and uses a computed
min/max instead. We should just always use that.
(Of course since keycodes/evdev currently uses almost all of the
keycodes in the range it declares, including 255, this doesn't save any
memory for the common user right now).

Signed-off-by: Ran Benita <ran234@gmail.com>