drm/i915: hide mkwrite_device_info() better

drm/i915: hide mkwrite_device_info() better

The goal has been to just make device info a pointer to static const
data, i.e. the static const structs in i915_pci.c. See [1]. However,
there were issues with intel_device_info_runtime_init() clearing the
display sub-struct of device info on the !HAS_DISPLAY() path, which
consequently disables a lot of display functionality, like it
should. Looks like we'd have to cover all those paths, and maybe
sprinkle HAS_DISPLAY() checks in them, which we haven't gotten around
to.

In the mean time, hide mkwrite_device_info() better within
intel_device_info.c by adding a intel_device_info_driver_create() for
the very early initialization of the device info and initial runtime
info. This also lets us declutter i915_drv.h a bit, and stops promoting
mkwrite_device_info() as something that could be used.

[1] https://lore.kernel.org/r/a0422f0a8ac055f65b7922bcd3119b180a41e79e.1655712106.git.jani.nikula@intel.com

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230411105643.292416-1-jani.nikula@intel.com