vmspawn: move VMSPAWN_PCIE_HOTPLUG_SPARES to vmspawn-qmp.h

Pure code motion, in preparation for the bridge-side hotplug machinery
that needs the same constant to size its hotplug_port_owner[] array. The
unsigned-suffix on the literal is dropped: the only consumer that compares
against unsigned (vmspawn.c's pcie-port assert) is happy with a plain
integer literal.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

src/vmspawn/vmspawn-qmp.h

@@ -5,6 +5,8 @@
 
 #include "shared-forward.h"
 
+#define VMSPAWN_PCIE_HOTPLUG_SPARES 10
+
 /* Pending job continuation — called when a QMP background job reaches "concluded" state.
  * Used by blockdev-create to chain remaining drive setup after the job completes. */
 typedef int (*pending_job_callback_t)(QmpClient *qmp, void *userdata);

src/vmspawn/vmspawn.c

@@ -102,9 +102,6 @@
 #define DISK_SERIAL_MAX_LEN_NVME        20
 #define DISK_SERIAL_MAX_LEN_VIRTIO_BLK  20
 
-/* Spare pcie-root-ports reserved for future runtime hotplug beyond the pre-wired devices. */
-#define VMSPAWN_PCIE_HOTPLUG_SPARES 10u
-
 /* An enum controlling how auxiliary state for the VM are maintained, i.e. the TPM state and the EFI variable
  * NVRAM. */
 typedef enum StateMode {