nfsd: remove superfluous KERN_INFO

dprintk already provides a KERN_* prefix; this KERN_INFO just shows up
as some odd characters in the output.

Simplify the message a bit while we're there.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>