The kernel patch *-mips_module_reloc.patch breaks dynamic ftrace as
dynamic ftrace depends on -mlong-calls.
See http://patchwork.linux-mips.org/patch/675/
Thus we always set -mlong-calls if the kernel is being
compiled with dynamic ftrace support.
Signed-off-by: Vincent Wiemann <webmaster@codefetch.de>
(cherry picked from commit 076d2ea6829855ee14ebd65230146eb27ee16750)