[PATCH] USB: fix in usb_calc_bus_time

This patch does the same swap, i.e. use the ISO macro if (isoc).
Additionally, it fixes the return value - the usb_calc_bus_time function
returns the time in nanoseconds (I didn't notice that before) while the
HS_USECS and HS_USECS_ISO are microseconds.  This fixes the function to
return nanoseconds always, and adjusts ehci-q.c (the only high-speed
caller of the function) to wrap the call in NS_TO_US().

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>