anv: Fix cache UUID generation.

I asked Emil to switch from 0 (success) vs. -1 (fail) to use a boolean
in my review comments.  The "not" went missing.  Easy mistake, but the
result is that nothing runs at all :)

Fix whitespace while we're here too.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>

src/intel/vulkan/anv_device.c

@@ -75,8 +75,8 @@ anv_device_get_cache_uuid(void *uuid)
    uint32_t timestamp;
 
    memset(uuid, 0, VK_UUID_SIZE);
-   if (anv_get_function_timestamp(anv_device_get_cache_uuid, &timestamp))
-         return false;
+   if (!anv_get_function_timestamp(anv_device_get_cache_uuid, &timestamp))
+      return false;
 
    snprintf(uuid, VK_UUID_SIZE, "anv-%d", timestamp);
    return true;