This adds a driver supporting a family of I2C port expanders from Maxim,
which includes the MAX7319 and MAX7320-7327 chips.

[dbrownell@users.sourceforge.net: minor fixes]
Signed-off-by: NJack Ren <jack.ren@marvell.com>
Signed-off-by: NEric Miao <eric.miao@marvell.com>
Acked-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>