NFS: Fix handful of compiler warnings in direct.c
NFS: Fix handful of compiler warnings in direct.c

This patch fixes a couple of signage issues that were causing an Oops
when running the LTP diotest4 test. get_user_pages() returns a signed
error, hence we need to be careful when comparing with the unsigned
number of pages from data->npages.

Signed-off-by: Chuck Lever <e7d8216bf9b1956703857d0050bd04192118f43d@oracle.com>
Signed-off-by: Trond Myklebust <6a1f9db795c9fc44be97d66ab114c53193bd3d13@netapp.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas