time: Add time_types.h

sys/time.h is the mandated include for many time related
defines. However, linux/time.h overlaps sys/time.h
significantly and this makes including both from userspace
or one from the other impossible.

This also means that userspace can get away with including
sys/time.h whenever it needs linux/time.h and this is what's
been happening in the user world usually.

But, we have new data types that we plan to use in the uapi time
interfaces also defined in the linux/time.h. But, we are unable
to use these types when sys/time.h is included.

Hence, move the new types to a new header, time_types.h.
We intend to eventually have all the uapi defines that the kernel
uses defined in this header.
Note that the plan is to replace uapi interfaces with timeval to
use __kernel_old_timeval, timespec to use __kernel_old_timespec etc.

Reported-by: Ran Rozenstein <ranro@mellanox.com>
Fixes: 9718475e ("socket: Add SO_TIMESTAMPING_NEW")
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>