Input: input_event - provide override for sparc64

The usec part of the timeval is defined as
__kernel_suseconds_t	tv_usec; /* microseconds */

Arnd noticed that sparc64 is the only architecture that defines
__kernel_suseconds_t as int rather than long.

This breaks the current y2038 fix for kernel as we only access and define
the timeval struct for non-kernel use cases.  But, this was hidden by an
another typo in the use of __KERNEL__ qualifier.

Fix the typo, and provide an override for sparc64.

Fixes: 152194fe ("Input: extend usable life of event timestamps to 2106 on 32 bit systems")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>