usb: dwc3: omap: fix up error path on probe()

Even if pm_runtime_get*() fails, we *MUST* call
pm_runtime_put_sync() before disabling PM.

While at it, remove superfluous dwc3_omap_disable_irqs()
in error path.

Signed-off-by: Felipe Balbi <balbi@kernel.org>
[nsekhar@ti.com: patch description updates]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>