hwmon/w83781d: Drop REALLY_SLOW_IO setting

hwmon/w83781d: Drop REALLY_SLOW_IO setting

In w83781d_isa_found() there is REALLY_SLOW_IO defined around some port
accesses, probably in order to wait between multiple accesses.

Unfortunately this isn't making any difference compared to not having
this define since more than a decade, as REALLY_SLOW_IO needs to be
defined while "#include <asm/io.h>" is called to have an effect.

As there seem not to be any outstanding issues in spite of this having
no effect, just drop the "#define" and add a remark to the related
comment.

Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20251126162018.5676-4-jgross@suse.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>