ehci-mxc: remove incorrect comment

The USB port to be used is determined by CONFIG_MXC_USB_PORT.
So, it appears that the comment is not correct. Remove it.

Signed-off-by: Wolfgang Grandegger <wg@denx.de>
diff --git a/drivers/usb/host/ehci-mxc.c b/drivers/usb/host/ehci-mxc.c
index a0cfbb7..f403d49 100644
--- a/drivers/usb/host/ehci-mxc.c
+++ b/drivers/usb/host/ehci-mxc.c
@@ -120,7 +120,6 @@
 
 	udelay(80);
 
-	/* Take USB2 */
 	ehci = (struct usb_ehci *)(IMX_USB_BASE +
 		(0x200 * CONFIG_MXC_USB_PORT));
 	hccr = (struct ehci_hccr *)((uint32_t)&ehci->caplength);