{soc/intel/cmn/pcie, mb/google/volteer}: Rename `is_external` variable

Name a variable based on its utility. `is_external` variable adds
`ExternalFacingPort` _DSD property to an ACPI device hence
rename it to `add_acpi_external_facing_port`.

BUG=b:259716145
TEST=Build google/rex with this flag and verify it in SSDT at
runtime.

SSDT snippet:
   Name (_DSD, Package (0x04)  // _DSD: Device-Specific Data
   {
       ToUUID ("6211e2c0-58a3-4af3-90e1-927a4e0c55a4"),
       Package (0x01)
       {
           Package (0x02)
           {
               "HotPlugSupportInD3",
               One
           }
       },

       ToUUID ("efcc06cc-73ac-4bc3-bff0-76143807c389"),
       Package (0x01)
       {
           Package (0x02)
           {
               "ExternalFacingPort",
               One
           }
        }
    })

Signed-off-by: Kapil Porwal <kapilporwal@google.com>
Change-Id: I65100283ed9b65037c9890f28ecab41fcfa25d83
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69970
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions