Fix building with GCC 4.9

It doesn't like empty initializers.

Change-Id: If2988e60401155f87ee3369c77f00ccf9332012c
Signed-off-by: Evgeny Zinoviev <me@ch1p.io>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/36629
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

atavia.c

@@ -51,7 +51,7 @@
 const struct dev_entry ata_via[] = {
 	{PCI_VENDOR_ID_VIA, 0x3249, DEP, "VIA", "VT6421A"},
 
-	{},
+	{0},
 };
 
 static void atavia_chip_writeb(const struct flashctx *flash, uint8_t val, chipaddr addr);