usb: dwc3: Remove dev_err() on platform_get_irq() failure

Since commit 7723f4c5

 ("driver core: platform: Add an error message to
platform_get_irq*()"), platform_get_irq() will call dev_err() itself on
failure, so there is no need for the driver to also do this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Link: https://lore.kernel.org/r/20191005210449.3926-4-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>