net: phy: qca8337: Add switch driver for Atheros qca8337

This patch enables initial driver support for QCA8337 switch.
This switch driver supports the following features:
(1) configuring 4 Lan ports and 1 WAN port
(2) configuring internal PHY's of all the ports
(3) configuring VLAN settings
(4) support for switch internal register statistics info

Change-Id: Ie5241d2b8a06995291fcdfb67cd4901f22743ef6
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>