MIPS: mipsreg: remove duplicate MIPS_CONF4_FTLBSETS_SHIFT

MIPS: mipsreg: remove duplicate MIPS_CONF4_FTLBSETS_SHIFT

The MIPS_CONF4_FTLBSETS_SHIFT define is cut and pasted twice so we can
remove the second define.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: John Crispin <blogic@openwrt.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: kernel-janitors@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7063/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>