i915/snd_hdac: I915 subcomponent for the snd_hdac

Since we need multiple components for I915 for different purposes
(Audio & Mei_hdcp), we adopt the subcomponents methodology introduced
by the previous patch (mentioned below).

	Author: Daniel Vetter <daniel.vetter@ffwll.ch>
	Date:   Mon Jan 28 17:08:20 2019 +0530

	    components: multiple components for a device

Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by-by: Ramalingam C <ramalinagm.c@intel.com> (commit message)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> (code)
cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc: Russell King <rmk+kernel@arm.linux.org.uk>
cc: Rafael J. Wysocki <rafael@kernel.org>
cc: Jaroslav Kysela <perex@perex.cz>
cc: Takashi Iwai <tiwai@suse.com>
cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
cc: Jani Nikula <jani.nikula@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190207232759.14553-4-daniel.vetter@ffwll.ch