firewire: nosy: Replace timeval with timespec64

'struct timeval' uses a 32 bit field for its 'seconds' value which
will overflow in year 2038 and beyond. This patch replaces the use
of timeval in nosy.c with timespec64 which doesn't suffer from y2038
issue. The code is correct as is - since it is only using the
microseconds portion of timeval. However, this patch does the
replacement as part of a larger effort to remove all instances of
'struct timeval' from the kernel (that would help identify cases
where the code is actually broken).

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>