kdbus: avoid the use of struct timespec

kdbus: avoid the use of struct timespec

I did a routine check for new users of 'timespec', which we are trying to remove
from the kernel in order to survive y2038. kdbus came up and looks particularly
trivial to clean up.

This changes the three ktime_get_ts() variants used in kdbus to ktime_get_ns(),
which aside from removing timespec also simplifies the code and makes it
slightly more efficient by avoiding a two-way conversion.

Change-Id: Ia9a2da376609d8e0ec6e311e4c9f27ed3702350e
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Osmialowski <p.osmialowsk@samsung.com>