ehci_sh_platdata was never used, remove it. It can be resurrected from
git history when needed.

This basically reverts commit 3e0c70d0 ("usb: ehci-sh: Add PHY
init function with platform data").
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Link: https://lore.kernel.org/r/20191206132849.29406-1-geert+renesas@glider.beSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>