qemu: fix build error introduced by CVE-2021-3929 fix

qemu: fix build error introduced by CVE-2021-3929 fix

The patch for CVE-2021-3929 applied on dunfell returns a value for a
void function. This results in the following compiler warning/error:

hw/block/nvme.c:77:6: error: void function
'nvme_addr_read' should not return a value [-Wreturn-type]

return NVME_DATA_TRAS_ERROR;
^      ~~~~~~~~~~~~~~~~~~~~

In newer versions of qemu, the functions is changed to have a return
value, but that is not present in the version of qemu used in “dunfell”.

Backport some of the patches to correct this.

Signed-off-by: Gaurav Gupta <gauragup@cisco.com>
Signed-off-by: Gaurav Gupta <gauragup@cisco.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>