net: stmmac: Add driver for Qualcomm ethqos

Add glue driver to support Qualcomm ETHQOS using stmmac driver.

This is based on downstream driver written by Siddarth Gupta, Sunil
Kumar Paidimarri, Rahul Ankushrao Kawadgave, Nisha Menon, Jagadeesh
Babu Challagundla, Chaitanya Pratapa, Lakshit Tyagi, Suraj Jaiswal,
Sneh Shah and Ventrapragada Ravi Kanth

Change-Id: I944ea109f6751df25f611975be8c4a5075c04fa4
Co-developed-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: a7c30e62d4b89580c16023a4daba466f9fed35ae
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/


Signed-off-by: Sneh Shah <snehshah@codeaurora.org>