Revert "rpmsg: core: add support to power domains for devices"

This reverts commit 1ed3a930 which is
commit fe782aff upstream

Rafael reports that this patch causes problems:
	> -rc2 looks good. There is a problem on dragonboard during boot that was
	> introduced in v4.14.71 that I didn't notice last week. We'll bisect it
	> and report back later this week. dragonboard on the other branches (4.9,
	> 4.18, mainline) looks fine.

	As Dan pointed out, during validation, we have bisected this issue on
	a dragonboard 410c (can't find root device) to the following commit
	for v4.14:

	[1ed3a930] rpmsg: core: add support to power domains for devices

	There is an on-going discussion on "[PATCH] rpmsg: core: add support
	to power domains for devices" about this patch having other
	dependencies and breaking something else on v4.14 as well.

so drop it.

Reported-by: Rafael Tinoco <rafael.tinoco@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>