usb: dwc3: omap: remove IRQ_NOAUTOEN used with shared irq

IRQ_NOAUTOEN cannot be used with shared IRQs, since commit 04c848d3
("genirq: Warn when IRQ_NOAUTOEN is used with shared interrupts") and
kernel now throws a warn dump. But OMAP DWC3 driver uses this flag. As
per commit 12a7f17f

 ("usb: dwc3: omap: fix race of pm runtime with
irq handler in probe") that introduced this flag, PM runtime can race
with IRQ handler when deferred probing happens due to extcon,
therefore IRQ_NOAUTOEN needs to be set so that irq is not enabled until
extcon is registered.

Remove setting of IRQ_NOAUTOEN and move the registration of
shared irq to a point after dwc3_omap_extcon_register() and
of_platform_populate(). This avoids possibility of probe deferring and
above said race condition.

Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>