MIPS: Kconfig: remove HAVE_LATENCYTOP_SUPPORT

HAVE_LATENCYTOP_SUPPORT was removed all together in commit da48d094


("Kconfig: remove HAVE_LATENCYTOP_SUPPORT"). This commit removes a
leftover in the MIPS Kconfig.

Signed-off-by: Fabian Mewes <architekt@coding4coffee.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org