getting rid of sys/nfs/nfs_lock.c

Hi,

sys/nfs/nfs_lock.c uses Giant. Since it has not been used by default since
March 2008, I suspect it can be removed from head without any impact.
Post March 2008, the only way this code could be executed is by both
building a kernel without "options NFSLOCKD" and deleting nfslockd.ko
from the kernel boot directory and then running rpc.lockd on the system.

I doubt anyone has been doing both of the above, but if you think it is
still useful, please speak up. (I have an untested patch that replaces Giant
with a regular mutex. I realized this code is not used when I trying to test it.;-)

Also, if it seems appropriate, I could commit a patch that makes it print out
"deprecated and going away before FreeBSD 13" message, but I doubt anyone
will ever see it.
Should I do such a message and wait a few months for the deletion?

Thanks for your comments, rick
ps: The current patch that prepares the kernel for deletion of sys/nfs/nfs_lock.c
     is in reviews.freebsd.org/D22933.