soc: qcom: Add support for power collapse

Adds handling interfaces between kernel clients and rmnet
driver. It enables the rmnet driver to create/delete DFC/WDA
clients and provides the common functionality for data flow control
and power save features

CRs-Fixed: 2277101
Change-Id: I212f00c7b68cc89371b7c90378616133534d7cc3
Acked-by: Ning Cai <ncai@qti.qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: Conner Huff <chuff@codeaurora.org>