xfs: Fix assert failure in xfs_setattr_size()

An assert failure is triggered by syzkaller test due to
ATTR_KILL_PRIV is not cleared before xfs_setattr_size.
As ATTR_KILL_PRIV is not checked/used by xfs_setattr_size,
just remove it from the assert.

Signed-off-by: Yumei Huang <yuhuang@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/xfs/xfs_iops.c

@@ -846,7 +846,7 @@ xfs_setattr_size(
 	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
 	ASSERT(S_ISREG(inode->i_mode));
 	ASSERT((iattr->ia_valid & (ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
-		ATTR_MTIME_SET|ATTR_KILL_PRIV|ATTR_TIMES_SET)) == 0);
+		ATTR_MTIME_SET|ATTR_TIMES_SET)) == 0);
 
 	oldsize = inode->i_size;
 	newsize = iattr->ia_size;