char: Skip CLI aliases in query-chardev-backends

char: Skip CLI aliases in query-chardev-backends

The aliases "tty" and "parport" are only valid on the command line, QMP
commands like chardev-add don't know them. query-chardev-backends should
describe QMP and therefore not include them in the list of available
backends.

Signed-off-by: Kevin Wolf <[email protected]>
Acked-by: Paolo Bonzini <[email protected]>
Message-Id: <20210311164253[email protected]>
Reviewed-by: Markus Armbruster <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>