phy: sun4i-usb: Remove unused of_gpio.h

of_gpio.h is deprecated and subject to remove. The drivers in question
don't use it, simply remove the unused header.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20241031104631.2454581-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>