firmware: dmi-sysfs: handle HAS_IOPORT=n

firmware: dmi-sysfs: handle HAS_IOPORT=n

In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
not being declared. We thus need to guard sections of code calling them
as alternative access methods.

Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20230522105049.1467313-11-schnelle@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>