In preparation for addition of other Qcom PHY and to tidy things up,
move the at803x PHY driver to dedicated directory.

The same order in the Kconfig selection is saved.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240129141600.2592-2-ansuelsmth@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>