hw/nvme: fix memory leak in nvme_dsm

The allocated memory to hold LBA ranges leaks in the nvme_dsm function. This
happens because the allocated memory for iocb->range is not freed in all
error handling paths.

Fix this by adding a free to ensure that the allocated memory is properly freed.

ASAN log:
==3075137==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 480 byte(s) in 6 object(s) allocated from:
    #0 0x55f1f8a0eddd in malloc llvm/compiler-rt/lib/asan/asan_malloc_linux.cpp:129:3
    #1 0x7f531e0f6738 in g_malloc (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x5e738)
    qemu#2 0x55f1faf1f091 in blk_aio_get block/block-backend.c:2583:12
    qemu#3 0x55f1f945c74b in nvme_dsm hw/nvme/ctrl.c:2609:30
    qemu#4 0x55f1f945831b in nvme_io_cmd hw/nvme/ctrl.c:4470:16
    qemu#5 0x55f1f94561b7 in nvme_process_sq hw/nvme/ctrl.c:7039:29

Cc: qemu-stable@nongnu.org
Fixes: d7d1474 ("hw/nvme: reimplement dsm to allow cancellation")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>

hw/nvme/ctrl.c

@@ -2591,6 +2591,7 @@ static void nvme_dsm_cb(void *opaque, int ret)
 done:
     iocb->aiocb = NULL;
     iocb->common.cb(iocb->common.opaque, iocb->ret);
+    g_free(iocb->range);
     qemu_aio_unref(iocb);
 }