drm/radeon: fix semaphore value init

Semaphore values have 64 bits, not 32. This fixes a very subtle bug
that disables synchronization when the upper 32bits wasn't zero.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Reviewed-By: NGrigori Goronzy <greg@chown.ath.cx>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_semaphore.c

@@ -34,7 +34,7 @@
 int radeon_semaphore_create(struct radeon_device *rdev,
 			    struct radeon_semaphore **semaphore)
 {
-	uint32_t *cpu_addr;
+	uint64_t *cpu_addr;
 	int i, r;
 
 	*semaphore = kmalloc(sizeof(struct radeon_semaphore), GFP_KERNEL);