drivers/cpufreq/db8500-cpufreq: remove references to cpu_*_map.

This has been obsolescent for a while; time for the final push.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dave Jones <davej@redhat.com>
Cc: cpufreq@vger.kernel.org
Cc: Sundar Iyer <sundar.iyer@stericsson.com>
Cc: Martin Persson <martin.persson@stericsson.com>
Cc: Jonas Aaberg <jonas.aberg@stericsson.com>