drivers: move the early platform device support to arch/sh

SuperH is the only user of the current implementation of early platform
device support. We want to introduce a more robust approach to early
probing. As the first step - move all the current early platform code
to arch/sh.

In order not to export internal drivers/base functions to arch code for
this temporary solution - copy the two needed routines for driver
matching from drivers/base/platform.c to arch/sh/drivers/platform_early.c.

Also: call early_platform_cleanup() from subsys_initcall() so that it's
called after all early devices are probed.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Rich Felker <dalias@libc.org>
Link: https://lore.kernel.org/r/20191003092913.10731-2-brgl@bgdev.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>