drm/i915: Add support for LMEM PCIe resizable bar

drm/i915: Add support for LMEM PCIe resizable bar

Add support for the local memory PICe resizable bar, so that
local memory can be resized to the maximum size supported by the device,
and mapped correctly to the PCIe memory bar. It is usual that GPU
devices expose only 256MB BARs primarily to be compatible with 32-bit
systems. So, those devices cannot claim larger memory BAR windows size due
to the system BIOS limitation. With this change, it would be possible to
reprogram the windows of the bridge directly above the requesting device
on the same BAR type.

v2:Moved code to gt/intel_region_lmem.c and used only
single underscore for function names.(Jani)

v3: Optimised code.

Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Cc: Michael J Ruhl <michael.j.ruhl@intel.com>
Cc: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Priyanka Dandamudi <priyanka.dandamudi@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220713130209.2573233-2-priyanka.dandamudi@intel.com