Change FreeBSD #ifdef into #if defined()

Corresponding to flashrom svn r393 and coreboot v2 svn r3898.
Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Peter Stuge <peter@stuge.se>

flash.h

@@ -30,7 +30,7 @@
 #include <stdint.h>
 #include <stdio.h>
 
-#ifdef __FreeBSD__
+#if defined(__FreeBSD__)
   #include <machine/cpufunc.h>
   #define off64_t off_t
   #define lseek64 lseek