MAINTAINERS: Add common/spl/spl_dfu to DFU entry

This was not listed as part of the DFU entry.

Add it to make sure that the DFU maintainers get CC'ed on
patches for spl_dfu.

Link: https://lore.kernel.org/r/20250618-maintainers-dfu-spl-v1-1-03f4bc745e36@kernel.org
Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
1 file changed