drivers: phy: add generic PHY framework

drivers: phy: add generic PHY framework

The PHY framework provides a set of APIs for the PHY drivers to
create/destroy a PHY and APIs for the PHY users to obtain a reference to the
PHY with or without using phandle. For dt-boot, the PHY drivers should
also register *PHY provider* with the framework.

PHY drivers should create the PHY by passing id and ops like init, exit,
power_on and power_off. This framework is also pm runtime enabled.

The documentation for the generic PHY framework is added in
Documentation/phy.txt and the documentation for dt binding can be found at
Documentation/devicetree/bindings/phy/phy-bindings.txt

Cc: Tomasz Figa <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Kishon Vijay Abraham I <[email protected]>
Acked-by: Felipe Balbi <[email protected]>
Tested-by: Sylwester Nawrocki <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>