Fix: ctf-writer: field_type_common_has_known_id always returns true

Fix: ctf-writer: field_type_common_has_known_id always returns true

I get this when building with gcc:

      CC       event.lo
    In file included from /home/simark/src/babeltrace/src/ctf-writer/event.h:42,
                     from /home/simark/src/babeltrace/src/ctf-writer/event.c:45:
    /home/simark/src/babeltrace/src/ctf-writer/fields.h: In function ‘field_type_common_has_known_id’:
    /home/simark/src/babeltrace/src/ctf-writer/fields.h:291:53: error: logical ‘or’ of collectively exhaustive tests is always true [-Werror=logical-op]
      291 |  return (int) ft->id > BT_CTF_FIELD_TYPE_ID_UNKNOWN ||
          |

Indeed, the logical expression there always returns true.  Change the ||
for a &&, which is what I think was meant here.

Change-Id: I0dbfb074e97b96b8f727f85628a544c412d2221c
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2272
Reviewed-by: Francis Deslauriers <francis.deslauriers@efficios.com>