util/inteltool: powermgt: initialize register size variables

Initialize register size variables to prevent segfaults.

Change-Id: Ib89bf6f7c7582efdea1c54d1316ed8f33a87cfcc
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39513
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/inteltool/powermgt.c

@@ -669,7 +669,7 @@ static const io_register_t i63xx_pm_registers[] = {
 
 int print_pmbase(struct pci_dev *sb, struct pci_access *pacc)
 {
-	size_t i, size;
+	size_t i, size = 0;
 	uint16_t pmbase;
 	const io_register_t *pm_registers;
 	uint64_t pwrmbase_phys = 0;