asm-generic/io.h: Remove I/O port accessors for HAS_IOPORT=n

asm-generic/io.h: Remove I/O port accessors for HAS_IOPORT=n

With all subsystems and drivers either declaring their dependence on
HAS_IOPORT or fencing I/O port specific code sections we can finally
make inb()/outb() and friends compile-time dependent on HAS_IOPORT as
suggested by Linus in the linked mail. The main benefit of this is that
on platforms such as s390 which have no meaningful way of implementing
inb()/outb() their use without the proper HAS_IOPORT dependency will
result in easy to catch and fix compile-time errors instead of compiling
code that can never work.

Link: https://lore.kernel.org/lkml/CAHk-=wg80je=K7madF4e7WrRNp37e3qh6y10Svhdc7O8SZ_-8g@mail.gmail.com/
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>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Maciej W. Rozycki <macro@orcam.me.uk>
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Acked-by: Jaroslav Kysela <perex@perex.cz>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net> # for ARCH=um
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Kalle Valo <kvalo@kernel.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>