x86-64, NUMA: Unify {acpi|amd}_{numa_init|scan_nodes}() arguments and return values

The functions used during NUMA initialization - *_numa_init() and
*_scan_nodes() - have different arguments and return values.  Unify
them such that they all take no argument and return 0 on success and
-errno on failure.  This is in preparation for further NUMA init
cleanups.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/setup.c

@@ -995,12 +995,12 @@ void __init setup_arch(char **cmdline_p)
 	/*
 	 * Parse SRAT to discover nodes.
 	 */
-	acpi = acpi_numa_init();
+	acpi = !acpi_numa_init();
 #endif
 
 #ifdef CONFIG_AMD_NUMA
 	if (!acpi)
-		amd = !amd_numa_init(0, max_pfn);
+		amd = !amd_numa_init();
 #endif
 
 	initmem_init(acpi, amd);