x86/pci: Rename acpi_mcfg_check_entry() to acpi_mcfg_valid_entry()

"acpi_mcfg_check_entry()" doesn't give a hint about what the return value
means.  Rename it to "acpi_mcfg_valid_entry()", convert the return value to
bool, and update the return values and callers to match so testing
"if (acpi_mcfg_valid_entry())" makes sense.

Link: https://lore.kernel.org/r/20231121183643.249006-6-helgaas@kernel.org


Tested-by: Tomasz Pala <gotar@polanet.pl>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>