Fix buffer overflow in slin sample frames generation.

The length of frames retured by sample functions was twice as large as
real, what caused global buffer overflow caught by AddressSanitizer.

ASTERISK-24717 #close
Reported by: Badalian Vyacheslav

Change-Id: Iec2fe682aef13e556684912f906bedf7c18229c6

include/asterisk/slin.h

@@ -62,7 +62,7 @@ static inline struct ast_frame *slin8_sample(void)
 {
 	static struct ast_frame f = {
 		.frametype = AST_FRAME_VOICE,
-		.datalen = sizeof(ex_slin8) * 2,
+		.datalen = sizeof(ex_slin8),
 		.samples = ARRAY_LEN(ex_slin8),
 		.mallocd = 0,
 		.offset = 0,
@@ -79,7 +79,7 @@ static inline struct ast_frame *slin16_sample(void)
 {
 	static struct ast_frame f = {
 		.frametype = AST_FRAME_VOICE,
-		.datalen = sizeof(ex_slin16) * 2,
+		.datalen = sizeof(ex_slin16),
 		.samples = ARRAY_LEN(ex_slin16),
 		.mallocd = 0,
 		.offset = 0,