shared: Add timespec_from_proto helper function

Add helper function to convert tv_sec_hi, tv_sec_lo, tv_nsec triplets,
used for sending high-resolution timestamp data over the wayland
protocol, to struct timespec values. Replace existing conversion code
with the helper function.

Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

clients/presentation-shm.c

@@ -39,6 +39,7 @@
 #include <wayland-client.h>
 #include "shared/helpers.h"
 #include "shared/zalloc.h"
+#include "shared/timespec-util.h"
 #include "shared/os-compatibility.h"
 #include "presentation-time-client-protocol.h"
 
@@ -383,14 +384,6 @@ timespec_to_ms(const struct timespec *ts)
 	return (uint32_t)ts->tv_sec * 1000 + ts->tv_nsec / 1000000;
 }
 
-static void
-timespec_from_proto(struct timespec *tm, uint32_t tv_sec_hi,
-		    uint32_t tv_sec_lo, uint32_t tv_nsec)
-{
-	tm->tv_sec = ((uint64_t)tv_sec_hi << 32) + tv_sec_lo;
-	tm->tv_nsec = tv_nsec;
-}
-
 static int
 timespec_diff_to_usec(const struct timespec *a, const struct timespec *b)
 {