usb: phy: twl4030-usb: ignore duplicate events

In some rare cases we may get multiple interrupts that will generate
duplicate omap_musb_mailbox() calls. This is a problem because each
VBUS/ID event generates runtime_pm call in OMAP glue code, causing
unbalanced gets or puts and breaking PM.

The same goes for initial state, glue already defaults to "no cable"
state, so only bother it if we have VBUS or ID.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>