gpu: nova-core: fix packed registry table size

`PACKED_REGISTRY_TABLE::size` describes the entire table, including its
fixed-size header. `SetRegistry` currently initializes it with only the
variable payload length, omitting the 8 bytes header.

Fix this by using `CommandToGsp::size` to obtain the actual command
size, including its header.

Fixes: 19b0a6e7c2 ("gpu: nova-core: gsp: Add SetRegistry command")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/r/20260722075253.B6DDB1F00A3D@smtp.kernel.org
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260723-nova-registry-size-fix-v1-1-8f471ba00ab4@nvidia.com
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

drivers/gpu/nova-core/gsp/commands.rs

@@ -127,10 +127,7 @@ impl CommandToGsp for SetRegistry {
     type InitError = Infallible;
 
     fn init(&self) -> impl Init<Self::Command, Self::InitError> {
-        Self::Command::init(
-            self.entries.len() as u32,
-            self.variable_payload_len() as u32,
-        )
+        Self::Command::init(self.entries.len() as u32, self.size() as u32)
     }
 
     fn variable_payload_len(&self) -> usize {