amdfam10 boards: Call get_bus_conf() just once

It has to be called once before PIRQ and MP table generation.

Change-Id: I238c6b4810404d320b36d4f6b4a161c1ff11c8d3
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/30630
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/mainboard/gigabyte/ma78gm/irq_tables.c

@@ -54,8 +54,6 @@ unsigned long write_pirq_routing_table(unsigned long addr)
 	u8 sum = 0;
 	int i;
 
-	get_bus_conf();		/* it will find out all bus num and apic that share with mptable.c and mptable.c and acpi_tables.c */
-
 	/* Align the table to be 16 byte aligned. */
 	addr += 15;
 	addr &= ~15;