lis3: update documentation and comments

Most of the documentation and comments were written when the driver was
only supporting one type of chip, only via ACPI/HP. Update the info to
the much clearer understanding that we have now.

Signed-off-by: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>