Remove unneeded include of <linux/nfsd/nfsfh.h> from nfsd.stp tapset
The nfsfh.h header file was removed from the kernel in 2014. The
nfsd.stp tapset attempting to include the header will cause the stap
module to fail to build. The nfsd.stp tapset does not require
anything from the the nfsfh.h header file and it can be safely
removed. This will eliminate the following systemtap examples
failures on newer kernels:
git://sourceware.org / systemtap.git / commit