{src,util}: Use NULL instead of 0 for pointer

Change-Id: I75fa4577055f25dde0a8b1044c005bba72cabd92
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26857
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/drivers/intel/fsp1_0/hob.c

@@ -167,7 +167,7 @@ void print_guid_type_attributes(void *Hobptr)
 void print_hob_type_structure(u16 Hobtype, void *Hoblistptr)
 {
 	u32 *Currenthob;
-	u32 *Nexthob = 0;
+	u32 *Nexthob = NULL;
 	u8  Lasthob = 0;
 	u32 Currenttype;
 	const char *Currenttypestr;

src/lib/libgcov.c

@@ -409,7 +409,7 @@ gcov_exit(void)
 		gcov_position_t summary_pos = 0;
 		gcov_position_t eof_pos = 0;
 		const char *fname, *s;
-		struct gcov_fn_buffer *fn_buffer = 0;
+		struct gcov_fn_buffer *fn_buffer = NULL;
 		struct gcov_fn_buffer **fn_tail = &fn_buffer;
 
 		fname = gi_ptr->filename;

src/mainboard/google/link/i915.c

@@ -157,7 +157,7 @@ static unsigned long times[4096];
 static int run(int index)
 {
 	int i, prev = 0;
-	struct iodef *id, *lastidread = 0;
+	struct iodef *id, *lastidread = NULL;
 	unsigned long u, t;
 	if (index >= niodefs)
 		return index;

src/northbridge/amd/lx/northbridgeinit.c

@@ -236,7 +236,7 @@ static void GLIUInit(struct gliutable *gl)
 	/* ************************************************************************** */
 static void GLPCIInit(void)
 {
-	struct gliutable *gl = 0;
+	struct gliutable *gl = NULL;
 	int i;
 	msr_t msr;
 	int msrnum, enable_preempt, enable_cpu_override;
@@ -604,7 +604,7 @@ static void rom_shadow_settings(void)
 
 static void enable_L1_cache(void)
 {
-	struct gliutable *gl = 0;
+	struct gliutable *gl = NULL;
 	int i;
 	msr_t msr;
 	uint8_t SysMemCacheProp;