USB: OHCI: fix new compiler warnings

This patch (as1515) fixes some unavoidably dumb compiler warnings:

  CC [M]  drivers/usb/renesas_usbhs/mod.o
In file included from drivers/usb/host/ohci-hcd.c:101:0:
drivers/usb/host/ohci-dbg.c: In function ‘fill_registers_buffer’:
drivers/usb/host/ohci-dbg.c:656:2: warning: the comparison will always evaluate as ‘true’ for the address of ‘next’ will never be NULL [-Waddress]
drivers/usb/host/ohci-dbg.c:675:3: warning: the comparison will always evaluate as ‘true’ for the address of ‘next’ will never be NULL [-Waddress]

Instead of trying to fix the macro to work under all cirumstances,
just add a second macro for use in cases where the "next" argument is
the address of a local variable.

Unfortunately the macro cannot be replaced by a real subroutine,
because there's no va_list version of ohci_dbg() or dev_dbg().

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>