cpufreq: scpi: remove stale/outdated comment about the driver

Commit 343a8d17 ("cpufreq: scpi: remove arm_big_little dependency")
removed the arm_big_little dependency from scpi driver and doesn't
provide any ops to arm_big_little cpufreq driver. Lets remove that
stale comment.
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/scpi-cpufreq.c

 /*
  * System Control and Power Interface (SCPI) based CPUFreq Interface driver
  *
- * It provides necessary ops to arm_big_little cpufreq driver.
- *
  * Copyright (C) 2015 ARM Ltd.
  * Sudeep Holla <sudeep.holla@arm.com>
  *