CPUFREQ: Loongson2: Fix broken build due to incorrect include.

71eeedcf (MIPS: Lemote 2F: Fix build caused
by recent mass rename.) only fixed one instance of this issue in arch/mips
but missed a 2nd one in drivers/cpufreq/loongson2_cpufreq.c.

[ralf@linux-mips.org: dropped the one segment for the already fixed
instance and changed the other avoiding an include <path.h> without a /
because that's generally is a bad idea.]

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Patchwork: https://patchwork.linux-mips.org/patch/10659/