usb: musb: Add missing PM suspend and resume functions for 2430 glue

usb: musb: Add missing PM suspend and resume functions for 2430 glue

Looks like we are missing suspend and resume functions for pm_ops that
are needed to idle the hardware for system suspend for 2430 glue layer.

We can rely on the driver internal PM runtime state, and call driver
functions to idle the hardware on suspend if needed. There is no need
to add a dependency to PM runtime for system suspend here.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20210518074449.17070-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>