x86, mpparse: build fix

fix:

  LD      .tmp_vmlinux1
  arch/x86/kernel/built-in.o: In function `setup_arch':
  : undefined reference to `early_reserve_e820_mpc_new'

Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/asm-x86/mpspec.h

@@ -46,7 +46,11 @@ extern unsigned long mp_lapic_addr;
 
 extern void find_smp_config(void);
 extern void get_smp_config(void);
+#ifdef CONFIG_X86_MPPARSE
 extern void early_reserve_e820_mpc_new(void);
+#else
+static inline void early_reserve_e820_mpc_new(void) { }
+#endif
 
 void __cpuinit generic_processor_info(int apicid, int version);
 #ifdef CONFIG_ACPI