usb: dwc3: patches for v3.5 merge window

This pull request contains one workaround for a Silicon
Issue found on all RTL releases prior to 2.20a, which
would cause a metastability state on Run/Stop bit.

We also have some patches implementing a few extra Standard
requests introduced by USB3 spec (Set SEL and Set Isoch Delay),
as well as one patch, which has been pending for a long time,
implementing LPM support.

Last, but not least, we are splitting the host address space
out of the dwc3 core driver otherwise xHCI won't be able to
request_mem_region() its own address space. This patch is
only needed because we are (as we should) re-using the xHCI
driver, which is a completely separate module.

Together with these three big changes, come a few extra preparatory
patches which most move code around, define macros and so on, as
well as a fix for Isochronous transfers which hasn't been triggered
before.

[ resolved conflicts and build error in drivers/usb/dwc3/gadget.c - gregkh]