kernel: add Qualcomm NSS dataplane ethernet driver

kernel: add Qualcomm NSS dataplane ethernet driver

Qualcomm NSS-DP is as its name says Qualcomms ethernet driver for the NSS
subsystem (Networking subsystem) built-into various Qualcomm SoCs.

It has 2 modes of operation:
* Without NSS FW and rest of code required for offloading

This is the one that we will use as the amount of kernel patching required
for NSS offloading and the fact that its not upstreamable at all makes it
unusable for us.

Driver in this mode is rather basic, it currently only offers NAPI GRO
(Added by us as part of the fixup) and basically relies on the powerfull
CPU to get good throughput.

* With NSS FW and rest of code required for offloading

In this mode, driver just registers the interfaces and hooks them into
NSS-ECM to allow offloading.
This mode is not viable for use in OpenWrt due to reasons already described
above.

This driver is required for ipq807x to have wired networking until a better
one is available, so lets add the fixed-up version for 5.15 for now.

Signed-off-by: Robert Marko <robimarko@gmail.com>