drm/i915: Use struct resource for memory region IO as well

mem->region is a struct resource, but mem->io_start and
mem->io_size are not for whatever reason. Let's unify this
and convert the io stuff into a struct resource as well.
Should make life a little less annoying when you don't have
juggle between two different approaches all the time.

Mostly done using cocci (with manual tweaks at all the
places where we mutate io_size by hand):
@@
struct intel_memory_region *M;
expression START, SIZE;
@@
- M->io_start = START;
- M->io_size = SIZE;
+ M->io = DEFINE_RES_MEM(START, SIZE);

@@
struct intel_memory_region *M;
@@
- M->io_start
+ M->io.start

@@
struct intel_memory_region M;
@@
- M.io_start
+ M.io.start

@@
expression M;
@@
- M->io_size
+ resource_size(&M->io)

@@
expression M;
@@
- M.io_size
+ resource_size(&M.io)

Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Acked-by: Nirmoy Das <nirmoy.das@intel.com>
Tested-by: Paz Zcharya <pazz@chromium.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240202224340.30647-2-ville.syrjala@linux.intel.com