AMD geode: Avoid conflicting main() declaration

Declaration of main in cpu/amd/car.h conflicts with the
definition of main required for x86/postcar.c in main_decl.h.

Change-Id: I19507b89a1e2ecf88ca574c560d4a9e9a3756f37
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/18615
Tested-by: build bot (Jenkins)
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/include/cpu/amd/car.h

@@ -1,7 +1,9 @@
 #ifndef _CPU_AMD_CAR_H
 #define _CPU_AMD_CAR_H
 
-void main(unsigned long bist);
+#include <arch/cpu.h>
+
+void asmlinkage mainboard_romstage_entry(unsigned long bist);
 
 void cache_as_ram_main(unsigned long bist, unsigned long cpu_init_detectedx);
 void done_cache_as_ram_main(void);