usb: renesas_usbhs: revise the irq_vbus comments

Since the irq_vbus comments doesn't match with the current
implementation, this patch revises it. This patch also changes
new lines to reduce the source code lines.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>