intelblocks/pcie: Correct mapping between LCAP port and coreboot index

coreboot uses port index which is 0 based for all PCIe root ports.
In case of PCIe remapping logic, coreboot reads LCAP register from PCIe
configuration space which contains port number (mostly 1 based). This
assumption might not be true for all the ports in coreboot.

TBT's LCAP registers are returning port index which are based on 2.
coreboot's PCIe remapping logic returns port index based on index 1.

This patch adds variable to pcie_rp_config to pass lcap_port_base to the
pcie remapping function, so coreboot can map any n-based LCAP encoding
to 0-based indexing scheme.

This patch updates correct lcap_port_base variable for all PCIe root
ports for all SOCs, so that function returns correct 0-based index from
LCAP port number.

BUG=b:210933428
BRANCH=None
TEST=Check if code compiles for all ADL boards

Change-Id: I7f9c3c8e753b982e2ede1a41bf87d6355b82da0f
Signed-off-by: MAULIK V VAGHELA <maulik.v.vaghela@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61936
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/elkhartlake/chip.c

@@ -17,7 +17,7 @@
 #include <soc/soc_chip.h>
 
 static const struct pcie_rp_group pch_rp_groups[] = {
-	{ .slot = PCH_DEV_SLOT_PCIE,    .count = 7 },
+	{ .slot = PCH_DEV_SLOT_PCIE,    .count = 7, .lcap_port_base = 1 },
 	{ 0 }
 };