x86/pci: Simplify is_mmconf_reserved() messages

is_mmconf_reserved() takes a "with_e820" parameter that only determines the
message logged if it finds the MMCONFIG region is reserved.  Pass the
message directly, which will simplify a future patch that adds a new way of
looking for that reservation.  No functional change intended.

Link: https://lore.kernel.org/r/20230110180243.1590045-2-helgaas@kernel.org
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>