cpufreq: sparc: Don't mark cpufreq callbacks with __init

These callbacks can be called again by the cpufreq core after the driver
is initialized and must be kept around. We currently get section
mismatch build warnings.

Don't mark them with __init.

Fixes: dcfce7c2

 ("cpufreq: sparc: Don't allocate cpufreq_driver dynamically")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>