MIPS: Correct the comment for FPU emulator traps

Adjust the explanatory comment for FPU emulator traps according to
ba3049ed

 [MIPS: Switch FPU emulator trap to BREAK instruction.];
originally coming from `do_ade'.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9672/


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