USB: UHCI: Add support for GRLIB GRUSBHC controller

This patch adds support for the UHCI part of the GRLIB GRUSBHC controller
found on some LEON/GRLIB SoCs.

The UHCI HCD previously only supported controllers connected over PCI.
This patch adds support for the first non-PCI UHCI HC. I have tried to
replicate the solution used in ehci-hcd.c.

Tested on GR-LEON4-ITX board (LEON4/GRLIB with GRUSBHC) and x86 with Intel
UHCI HC.

Signed-off-by: Jan Andersson <jan@gaisler.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>