phy: add new phy_notify_state() api

phy: add new phy_notify_state() api

Add a new phy_notify_state() api that notifies and configures a phy for a
given state transition.

This is intended to be used by phy drivers which need to do some runtime
configuration of parameters that can't be handled by phy_calibrate() or
phy_power_{on|off}().

The first usage of this API is in the Samsung UFS phy that needs to issue
some register writes when entering and exiting the hibernate link state.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251112-phy-notify-pmstate-v5-1-39df622d8fcb@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>