[skus,cfg] Import the empty MLDSA library for DICE

Since lowRISC/opentitan#31054,
the DICE library needs to export a symbol to build the MLDSA
certificate (if any).

Signed-off-by: Amaury Pouly <amaury.pouly@gmail.com>

Author: pamaury

skus/cfg.bzl

@@ -13,7 +13,7 @@ EXT_EARLGREY_SKUS = {
     "emulation_open": {
         "otp": "em00",
         "ca_data": "@lowrisc_opentitan//sw/device/silicon_creator/manuf/keys/fake:ca_data",
-        "dice_libs": ["@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice"],
+        "dice_libs": ["@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice", "@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice_mldsa_empty"],
         "host_ext_libs": ["@provisioning_exts//open:ft_ext_lib"],
         "device_ext_libs": ["@provisioning_exts//open:personalize_fw_ext"],
         "ownership_libs": ["@lowrisc_opentitan//sw/device/silicon_creator/lib/ownership:test_owner"],
@@ -36,7 +36,7 @@ EXT_EARLGREY_SKUS = {
     "ot00_staging": {
         "otp": "ot00",
         "ca_data": "@lowrisc_opentitan//sw/device/silicon_creator/manuf/keys/fake:ca_data",
-        "dice_libs": ["@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice"],
+        "dice_libs": ["@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice", "@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice_mldsa_empty"],
         "host_ext_libs": ["@provisioning_exts//open:ft_ext_lib"],
         "device_ext_libs": ["@provisioning_exts//open:personalize_fw_ext"],
         "ownership_libs": ["@provisioning_exts//open/rom_ext:owner"],
@@ -52,7 +52,7 @@ EXT_EARLGREY_SKUS = {
     "ot00": {
         "otp": "ot00",
         "ca_data": "@provisioning_exts//open/keys/ca:ca_data",
-        "dice_libs": ["@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice"],
+        "dice_libs": ["@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice", "@lowrisc_opentitan//sw/device/silicon_creator/lib/cert:dice_mldsa_empty"],
         "host_ext_libs": ["@provisioning_exts//open:ft_ext_lib"],
         "device_ext_libs": ["@provisioning_exts//open:personalize_fw_ext"],
         "ownership_libs": ["@provisioning_exts//open/rom_ext:owner"],