staging: speakup: str initialization replaced with NULL where it was initialized with int

Fixed warnings in all of three files where the string was initilized with an integer instead of NULL
Signed-off-by: Shalin Mehta <shalinmehta85@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/speakup/main.c

@@ -90,7 +90,7 @@ const struct st_bits_data spk_punc_info[] = {
 	{"repeats", "()", CH_RPT},
 	{"extended numeric", "", B_EXNUM},
 	{"symbols", "", B_SYM},
-	{0, 0}
+	{NULL, NULL}
 };
 
 static char mark_cut_flag;

drivers/staging/speakup/speakup_audptr.c

@@ -39,7 +39,7 @@ static struct var_t vars[] = {
 	{ RATE, .u.n = {"\x05[r%d]", 10, 0, 20, 100, -10, NULL } },
 	{ PITCH, .u.n = {"\x05[f%d]", 80, 39, 4500, 0, 0, NULL } },
 	{ VOL, .u.n = {"\x05[g%d]", 21, 0, 40, 0, 0, NULL } },
-	{ TONE, .u.n = {"\x05[s%d]", 9, 0, 63, 0, 0, 0 } },
+	{ TONE, .u.n = {"\x05[s%d]", 9, 0, 63, 0, 0, NULL } },
 	{ PUNCT, .u.n = {"\x05[A%c]", 0, 0, 3, 0, 0, "nmsa" } },
 	{ DIRECT, .u.n = {NULL, 0, 0, 1, 0, 0, NULL } },
 	V_LAST_VAR

drivers/staging/speakup/varhandlers.c

@@ -46,7 +46,7 @@ static struct st_var_header var_headers[] = {
 	{ "direct", DIRECT, VAR_NUM, NULL, NULL },
 };
 
-static struct st_var_header *var_ptrs[MAXVARS] = { 0, 0, 0 };
+static struct st_var_header *var_ptrs[MAXVARS] = { NULL, NULL, NULL };
 
 static struct punc_var_t punc_vars[] = {
 	{ PUNC_SOME, 1 },