net: mscc: ocelot: extend watermark encoding function

net: mscc: ocelot: extend watermark encoding function

[ Upstream commit aa92d836d5c40a7e21e563a272ad177f1bfd44dd ]

The ocelot_wm_encode function deals with setting thresholds for pause
frame start and stop. In Ocelot and Felix the register layout is the
same, but for Seville, it isn't. The easiest way to accommodate Seville
hardware configuration is to introduce a function pointer for setting
this up.

Signed-off-by: Maxim Kochetkov <fido_max@inbox.ru>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>