USB: PHY: JZ4770: Fix static checker warning.

The commit 2a6c0b82 ("USB: PHY: JZ4770: Add support for new
Ingenic SoCs.") introduced the initialization function for different
chips, but left the relevant code involved in the resetting process
in the original function, resulting in uninitialized variable calls.

Fixes: 2a6c0b82 ("USB: PHY: JZ4770: Add support for new Ingenic SoCs.").
Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Link: https://lore.kernel.org/r/20200825081654.18186-2-zhouyanjie@wanyeetech.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/phy-jz4770.c

@@ -176,6 +176,7 @@ static int ingenic_usb_phy_init(struct usb_phy *phy)
 
 	/* Wait for PHY to reset */
 	usleep_range(30, 300);
+	reg = readl(priv->base + REG_USBPCR_OFFSET);
 	writel(reg & ~USBPCR_POR, priv->base + REG_USBPCR_OFFSET);
 	usleep_range(300, 1000);