hwmon: lm70: convert to device table matching

Make the code a little bit nicer, and shorter.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kaiwan N Billimoria <kaiwan@designergraphix.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>