remoteproc: stm32_rproc: Fix mailbox interrupts queuing

Manage interrupt coming from coprocessor also when state is
ATTACHED.

Fixes: 35bdafd ("remoteproc: stm32_rproc: Add mutex protection for workqueue")
Cc: stable@vger.kernel.org
Signed-off-by: Gwenael Treuveur <gwenael.treuveur@foss.st.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20240521162316.156259-1-gwenael.treuveur@foss.st.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Author: Gwenael Treuveur

drivers/remoteproc/stm32_rproc.c

@@ -294,7 +294,7 @@ static void stm32_rproc_mb_vq_work(struct work_struct *work)
 
 	mutex_lock(&rproc->lock);
 
-	if (rproc->state != RPROC_RUNNING)
+	if (rproc->state != RPROC_RUNNING && rproc->state != RPROC_ATTACHED)
 		goto unlock_mutex;
 
 	if (rproc_vq_interrupt(rproc, mb->vq_id) == IRQ_NONE)