usb: dwc3: exynos: Fix remove() function

usb: dwc3: exynos: Fix remove() function

The core DWC3 device node was not properly removed by the custom
dwc3_exynos_remove_child() function. Replace it with generic
of_platform_depopulate() which does that job right.

Fixes: adcf20dcd262 ("usb: dwc3: exynos: Use of_platform API to create dwc3 core pdev")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Cc: stable@vger.kernel.org
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20221110154131.2577-1-m.szyprowski@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>