symbols: remove useless identical groups optimization What this code does is, in case someone compile a keymap like -layout 'us,us,us' then only one group would be created. If there is anything which differentiates between any of the groups (e.g. a variant, another layout), then this is not done. This is pretty obscure, only saves a few kbytes in the final keymap, and if the user asked for it, why not let her? Signed-off-by: Ran Benita <ran234@gmail.com>