linux-imx

net: ethernet: add property "nvmem_macaddr_swap" to swap macaddr bytes order

ethernet controller driver call .of_get_mac_address() to get
the mac address from devictree tree, if these properties are
not present, then try to read from nvmem.

For example, read MAC address from nvmem:
of_get_mac_address()
	of_get_mac_addr_nvmem()
		nvmem_get_mac_address()

i.MX6x/7D/8MQ/8MM platforms ethernet MAC address read from
nvmem ocotp eFuses, but it requires to swap the six bytes
order.

The patch add optional property "nvmem_macaddr_swap" to swap
macaddr bytes order.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>