phy: usb: Leave some clocks running during suspend

phy: usb: Leave some clocks running during suspend

The PHY client driver does a phy_exit() call on suspend or rmmod and
the PHY driver needs to know the difference because some clocks need
to be kept running for suspend but can be shutdown on unbind/rmmod
(or if there are no PHY clients at all).

The fix is to use a PM notifier so the driver can tell if a PHY
client is calling exit() because of a system suspend or a driver
unbind/rmmod.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20211201180653.35097-2-alcooperx@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>