usb: musb: dsps: fix runtime pm for peripheral mode

Since the runtime PM support was added in musb, dsps relies on the timer
calling otg_timer() to activate the usb subsystem. However the driver
doesn't enable the timer for peripheral port, then the peripheral port is
unable to be enumerated by a host if the other usb port is disabled or in
peripheral mode too.

So let's start the timer for peripheral port too.

Fixes: ea2f35c0 ("usb: musb: Fix sleeping function called from invalid context for hdrc glue")
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>