topology: pre-process-dapm: add support for route objects

topology: pre-process-dapm: add support for route objects

DAPM route objects such as:
Object.Base.route."1" {
	source	"dai.SSP.0.dai.capture"
	sink	"buffer.2.1"
}

will be converted to:

SectionGraph."Endpoint.route.1" {
	index 0
	lines [
		"dai.SSP.0.capture, , buffer.2.1"
	]
}

If the source/sink names are references to objects within a parent pipeline
object, the index attribute value can be skipped and it will be
populated when the object is pre-processed

Object.Pipeline.volume-capture."1" {
	Object.Base.route."1" {
		source	"pga..0"
		sink	"buffer..0"
	}
}

The reference pga..0 will need to be resolved to
get the widget name pga.1.0 and buffer..0 will
be resolved to buffer.1.0 before creating the SectionGraph as follows:

SectionGraph."volume-capture.1.route.1" {
	index 2
	lines [
		"pga.1.0, , buffer.1.0"
	]
}

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>