soc/intel/cmn/pcie: Allow SoC to overwrite snoop/non-snoop latency

soc/intel/cmn/pcie: Allow SoC to overwrite snoop/non-snoop latency

The Intel SoC Meteor Lake requires a higher pcie max non-snoop and
snoop latency tolerance. Add config to let SoC overwrite the common
code settings if needed.

BUG=none
TEST=Boot google/rex and print/check if able to overwrite values.

Change-Id: Ic2b9a158d219e6c6e7f6e7f0ae0f093c1183b402
Signed-off-by: Bora Guvendik <bora.guvendik@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74141
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>