cifs: remove kmap lock and rsize limit

Now that we aren't abusing the kmap address space, there's no need for
this lock or to impose a limit on the rsize.

Signed-off-by: Jeff Layton <jlayton@redhat.com>

diff --cc fs/cifs/cifsfs.c
Simple merge

diff --cc fs/cifs/cifsglob.h
Simple merge

diff --cc fs/cifs/smb1ops.c
Simple merge

diff --cc fs/cifs/smb2ops.c
Simple merge