MIPS: Kconfig: replace OPROFILE=n to !OPROFILE

In Kconfig "=n" is not correct syntax, "!" is the preferred way for
false-positive expression.

Signed-off-by: Yang Shi <yang.shi@windriver.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12572/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>