There are currently 30 power domains, which puts us pretty close to the
limit with 32 bit masks. Prepare for the future and increase the limit
to 64 bit.

v2: Rebase
v3: s/unsigned long long/u64/ (Joonas)
    Allow the 64th bit of the mask to be used. (Joonas)

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170209093121.24410-1-ander.conselvan.de.oliveira@intel.com