drm: i915: remove timeval users

struct timeval is deprecated because it cannot represent times
past 2038. In this driver, the only use of this structure is
to capture debug information. This is easily changed to ktime_t,
which we then format as needed when printing it later.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20180117154916.219273-1-arnd@arndb.de


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>