src: Add missing 'void' in function definition

Change-Id: I7fa1f9402b177a036f08bf99c98a6191c35fa0b5
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61371
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jason Glenesk <jason.glenesk@gmail.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/northbridge/intel/gm45/iommu.c

@@ -8,7 +8,7 @@
 
 #include "gm45.h"
 
-void init_iommu()
+void init_iommu(void)
 {
 	/* FIXME: proper test? */
 	int me_active = pci_read_config8(PCI_DEV(0, 3, 0), PCI_CLASS_REVISION) != 0xff;