mfd: move drivers/i2c/chips/menelaus.c to drivers/mfd

ove the menelaus driver from drivers/i2c/chips to drivers/mfd
since it's more of a multi-function device than anything else,
and since Jean is trying to vanish drivers/i2c/chips ASAP.

One way to think of these chips are as the PMIC family most
used with OMAP2 generation chips.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>