x86: coding style fixes to arch/x86/kernel/setup_32.c

Fix:

  ERROR: do not initialise externals to 0 or NULL
Signed-off-by: NPaolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/setup_32.c

@@ -228,7 +228,7 @@ static inline void copy_edd(void)
 }
 #endif
 
-int __initdata user_defined_memmap = 0;
+int __initdata user_defined_memmap;
 
 /*
  * "mem=nopentium" disables the 4MB page tables.