drm/i915/gt: Use pci_rebar_size_supported()

drm/i915/gt: Use pci_rebar_size_supported()

PCI core provides pci_rebar_size_supported() that helps in checking if an
encoded BAR Size is supported for the BAR or not. Use it in
i915_resize_lmem_bar() to simplify code.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20251113180053.27944-7-ilpo.jarvinen@linux.intel.com