usb: Rename ehci-fsl.h to ehci-ci.h

Most of ehci-fsl header describe USB controller
designed by Chipidea and used by various SoC vendors.

This patch renames it to a generic header: ehci-ci.h
Contents of file are not changed (so it contains several
references to freescale SoCs).

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Acked-by: Marek Vasut <marex@denx.de>
Tested-by: Simon Glass <sjg@chromium.org>