fs: make operator<() for search ioctl inline

Perf blames this operator for >1% of instructions with -O2, and
70% of instructions without -O2.

Let the compiler inline the function.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

lib/fs.cc

@@ -756,12 +756,6 @@ namespace crucible {
 		return offset + len;
 	}
 
-	bool
-	BtrfsIoctlSearchHeader::operator<(const BtrfsIoctlSearchHeader &that) const
-	{
-		return tie(objectid, type, offset, len, transid) < tie(that.objectid, that.type, that.offset, that.len, that.transid);
-	}
-
 	bool
 	BtrfsIoctlSearchKey::do_ioctl_nothrow(int fd)
 	{