MIPS: Octeon: Workaround link failures with gcc-4.4.x 32-bits toolchains

When building with a gcc-4.4.x toolchain that is configured to produce
32-bits executables by default, we will produce __lshrti3 in sched_clock()
which is never resolved so the kernel fails to link. Unconditionally use
the inline assembly version as suggested by David Daney, which works around
the issue.

Signed-off-by: Florian Fainelli <florian@openwrt.org>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1514/
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>