mfd/db8500-prcmu: remove support for early silicon revisions

The DB8500 ED (Early Drop) and V1 are only available inside of
ST-Ericsson or partners, we have actively replaced and scrapped
these prototypes. All Nova products on the open market (such as
the Snowball board) are based on V2 and later ASIC variants.
So let us focus on supporting the silicon that will be used and
delete this to get a clear overview.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Samuel Ortiz <samuel.ortiz@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>