mainboard: Format irq_tables.c

Run the command below to format the files `irq_tables.c` of (mostly AMD)
mainboards correctly with GNU indent 2.2.10.

```
$ git grep -l 'if (sum != pirq->checksum) {' | xargs indent -l
```

Fix up the following two checkpatch.pl errors manually.

```
ERROR: that open brace { should be on the previous line
#1219: FILE: src/mainboard/gigabyte/ga_2761gxdk/irq_tables.c:129:
+			uint8_t reg[8] =
+			    { 0x41, 0x42, 0x43, 0x44, 0x60, 0x61, 0x62, 0x63 };

ERROR: that open brace { should be on the previous line
#1221: FILE: src/mainboard/gigabyte/ga_2761gxdk/irq_tables.c:131:
+			uint8_t irq[8] =
+			    { 0x0A, 0X0B, 0X0, 0X0a, 0X0B, 0X05, 0X0, 0X07 };

```

This is needed, so that follow-up commits, fixing checkpatch.pl errors
and warnings, won’t run into conflicts with the git commit hooks, when
for example, spaces instead of tabs are used for indentation.

Change-Id: If254723f3013377fb3b9b08dd5eca6b76730ec4a
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-on: https://review.coreboot.org/15932
Tested-by: build bot (Jenkins)
Reviewed-by: Jonathan A. Kollasch <jakllsch@kollasch.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/amd/olivehill/irq_tables.c

@@ -39,7 +39,6 @@ static void write_pirq_info(struct irq_info *pirq_info, u8 bus, u8 devfn,
 	pirq_info->rfu = rfu;
 }
 
-
 unsigned long write_pirq_routing_table(unsigned long addr)
 {
 	struct irq_routing_table *pirq;