cpufreq: scpi: Fix incorrect arm_big_little config dependency

Commit 343a8d17 (cpufreq: scpi: remove arm_big_little dependency)
removed the SCPI cpufreq dependency on arm_big_little cpufreq driver.
However the Kconfig entry still depends on ARM_BIG_LITTLE_CPUFREQ
which is clearly wrong.

This patch removes that unnecessary Kconfig dependency.

Fixes: 343a8d17

 (cpufreq: scpi: remove arm_big_little dependency)
Reported-by: Quentin Perret <quentin.perret@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>