sb/intel/i82801gx: Constify struct southbridge_intel_i82801gx_config

Change-Id: Ia5af84782d41a007be04c3dccc291b788ddfddfd
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40773
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/southbridge/intel/i82801gx/pcie.c b/src/southbridge/intel/i82801gx/pcie.c
index adf0e49..dcad322 100644
--- a/src/southbridge/intel/i82801gx/pcie.c
+++ b/src/southbridge/intel/i82801gx/pcie.c
@@ -166,7 +166,7 @@
 	int coalesce = 0;
 
 	if (dev->chip_info != NULL) {
-		struct southbridge_intel_i82801gx_config *config = dev->chip_info;
+		const struct southbridge_intel_i82801gx_config *config = dev->chip_info;
 		coalesce = config->pcie_port_coalesce;
 	}