phy: cpcap-usb: remove unneeded conversion to bool

Fix the following warning:
drivers/phy/motorola/phy-cpcap-usb.c:146:31-36: WARNING: conversion to
bool not needed here.
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Link: https://lore.kernel.org/r/1607598716-16108-1-git-send-email-tiantao6@hisilicon.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/motorola/phy-cpcap-usb.c

@@ -143,7 +143,7 @@ static bool cpcap_usb_vbus_valid(struct cpcap_phy_ddata *ddata)
 
 	error = iio_read_channel_processed(ddata->vbus, &value);
 	if (error >= 0)
-		return value > 3900 ? true : false;
+		return value > 3900;
 
 	dev_err(ddata->dev, "error reading VBUS: %i\n", error);