drm/i915: Convert the power well descriptor domain mask to an array of domains

The next patch converts the i915_power_well_desc::domain mask from a u64
mask to a bitmap. I didn't find a reasonably simple way to initialize
bitmaps statically, so prepare for the next patch here by converting the
masks to an array of domain enums and initing the masks from these
arrays during module loading.

v2: Clarify list vs. array in the commit message. (Jani)

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220414210657.1785773-8-imre.deak@intel.com