Deatch qca83xx PHY driver from at803x.

The QCA83xx PHYs implement specific function and doesn't use generic
at803x so it can be detached from the driver and moved to a dedicated
one.

Probe function and priv struct is reimplemented to allocate and use
only the qca83xx specific data. Unused data from at803x PHY driver
are dropped from at803x priv struct.

This is to make slimmer PHY drivers instead of including lots of bloat
that would never be used in specific SoC.

A new Kconfig flag QCA83XX_PHY is introduced to compile the new
introduced PHY driver.

As the Kconfig name starts with Qualcomm the same order is kept.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240129141600.2592-4-ansuelsmth@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>