usb: ehci-exynos: Use NULL instead of 0

The third argument of devm_of_phy_get expects a pointer.
Hence use NULL instead of 0. Fixes the following warning:
drivers/usb/host/ehci-exynos.c:91:51: warning: Using plain integer as NULL pointer

Signed-off-by: Sachin Kamat <sachin.kamat@samsung.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Vivek Gautam <gautam.vivek@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed