MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions

Commit c8a34581 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
added support for emulating the new R6 BC1{EQ,NE}Z branches but it missed
the case where the instruction that caused the exception was not on a DS.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Fixes: c8a34581 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10738/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>