net/phy/marvell: Expose IDs and flags in a .h and add dns323 LEDs setup flag

This moves the various known Marvell PHY IDs to include/linux/marvell_phy.h
along with dev_flags definitions for use by the driver.

I then added a flag that changes the PHY init code to setup the LEDs
config to the values needed to operate a dns323 rev C1 NAS.

I moved the existing "resistance" flag to the .h as well, though I've
been unable to find whoever sets this to convert it to use that constant.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>