amdfam10 boards: Drop global bus_isa variable

Value of the global is never evaluated.

Change-Id: I74106b0f5f033053288882a5bcd3c1dba3235ac0
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/30628
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/advansus/a785e-i/mptable.c

@@ -20,7 +20,6 @@
 #include <stdint.h>
 #include <cpu/amd/amdfam10_sysconf.h>
 
-extern int bus_isa;
 extern u8 bus_rs780[11];
 extern u8 bus_sb800[6];
 extern u32 apicid_sb800;
@@ -40,6 +39,7 @@ u8 intr_data[] = {
 static void *smp_write_config_table(void *v)
 {
 	struct mp_config_table *mc;
+	int bus_isa;
 	u32 dword = 0;
 	u8 byte;