serial: 8250: fix compile error with hub6_match_port() when compiled as a module

With CONFIG_SERIAL_8250_HUB6=m, we have the following compile error:

  ../drivers/tty/serial/8250/8250_hub6.c:46:6: error: redefinition of
       'hub6_match_port'

Fix hub6_match_port() prototype definition by using IS_REACHABLE() to
support both built-in and module values, and substitute empty prototype
otherwise.

Fixes: 3d406299d8 ("serial: 8250_hub6: add hub6_match_port()")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202607150717.2YxVdWpX-lkp@intel.com/
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20260715153707.4181828-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hugo Villeneuve 2026-07-15 11:37:05 -04:00 • committed by Greg Kroah-Hartman
commit 7ab80d1e72