USB: EHCI: Support controllers with big endian capability regs

The two first HC capability registers (CAPLENGTH and HCIVERSION)
are defined as one 8-bit and one 16-bit register. Most HC
implementations have selected to treat these registers as part
of a 32-bit register, giving the same layout for both big and
small endian systems.

This patch adds a new quirk, big_endian_capbase, to support
controllers with big endian register interfaces that treat
HCIVERSION and CAPLENGTH as individual registers.

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>