net: fix a new kernel-doc warning at dev.c

kernel-doc expects the function prototype to be just after
the kernel-doc markup, as otherwise it will get it all wrong:

	./net/core/dev.c:10036: warning: Excess function parameter 'dev' description in 'WAIT_REFS_MIN_MSECS'

Fixes: 0e4be9e5

 ("net: use exponential backoff in netdev_wait_allrefs")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>