usb: ehci: Add new EHCI driver for Broadcom STB SoC's

Add a new EHCI driver for Broadcom STB SoC's. A new EHCI driver
was created instead of adding support to the existing ehci platform
driver because of the code required to work around bugs in the EHCI
controller. The primary workaround is for a bug where the Core
violates the SOF interval between the first two SOFs transmitted after
resume. This only happens if the resume occurs near the end of a
microframe. The fix is to intercept the ehci-hcd request to complete
RESUME and align it to the start of the next microframe.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200512150019.25903-5-alcooperx@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>