cpufreq: apple: remove duplicate intializer

When -Woverride-init is enabled, gcc notices that the .attr
field is initialized twice:

drivers/cpufreq/apple-soc-cpufreq.c:331:27: error: initialized field overwritten [-Werror=override-init]
  331 |         .attr           = apple_soc_cpufreq_hw_attr,
      |                           ^~~~~~~~~~~~~~~~~~~~~~~~~

Remove the first one, since this is not actually used.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Eric Curtin <ecurtin@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>