[media] cec: pass parent device in register(), not allocate()

[media] cec: pass parent device in register(), not allocate()

The cec_allocate_adapter function doesn't need the parent device, only the
cec_register_adapter function needs it.

Drop the cec_devnode parent field, since devnode.dev.parent can be used
instead.

This change makes the framework consistent with other frameworks where the
parent device is not used until the device is registered.

Conflicts:
	Documentation/media/kapi/cec-core.rst
	drivers/media/i2c/adv7511.c
	drivers/media/i2c/adv7604.c
	drivers/media/i2c/adv7842.c
	drivers/media/platform/vivid/vivid-cec.c
	drivers/media/platform/vivid/vivid-cec.h
	drivers/media/platform/vivid/vivid-core.c
	drivers/media/usb/pulse8-cec/pulse8-cec.c
	drivers/staging/media/s5p-cec/s5p_cec.c
	drivers/staging/media/st-cec/stih-cec.c

Change-Id: Id7a687308c4d3f2bc63ed2e8a55229b4e71fd8ed
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Git-commit: f51e80804f084de269954d875c0892b081b7df3c
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
[rayz@codeaurora.org: make some changes to fix the cherry-pick conflicts: (1)
 discard the CEC documentation change. (2) discard the CEC adapter driver
 changes for other vendors.]
Signed-off-by: Ray Zhang <rayz@codeaurora.org>