i915: remove timespec_to_jiffies_timeout

This function has been unused since commit 5ed0bdf2 ("drm: i915:
Use nsec based interfaces"). Let's remove the definition as well now
to help get rid of all uses of 'timespec'.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180618153855.2126048-1-arnd@arndb.de

drivers/gpu/drm/i915/i915_drv.h

@@ -3700,14 +3700,6 @@ static inline unsigned long nsecs_to_jiffies_timeout(const u64 n)
         return min_t(u64, MAX_JIFFY_OFFSET, nsecs_to_jiffies64(n) + 1);
 }
 
-static inline unsigned long
-timespec_to_jiffies_timeout(const struct timespec *value)
-{
-	unsigned long j = timespec_to_jiffies(value);
-
-	return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
-}
-
 /*
  * If you need to wait X milliseconds between events A and B, but event B
  * doesn't happen exactly after event A, you record the timestamp (jiffies) of