nb/intel/x4x: Remove dead assignments

The call to `decode_pcie_bar` always initializes these values.

Change-Id: Iffdb2fc846a6fc1a1abc504370b6283e292b61c0
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44150
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/northbridge/intel/x4x/acpi.c

@@ -9,8 +9,7 @@
 
 unsigned long acpi_fill_mcfg(unsigned long current)
 {
-	u32 pciexbar = 0;
-	u32 length = 0;
+	u32 pciexbar, length;
 
 	if (!decode_pcie_bar(&pciexbar, &length))
 		return current;