mISDN: Deletion of unnecessary checks before the function call "vfree"

The vfree() function performs also input parameter validation. Thus the test
around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/isdn/mISDN/l1oip_codec.c

@@ -312,10 +312,8 @@ l1oip_ulaw_to_alaw(u8 *data, int len, u8 *result)
 void
 l1oip_4bit_free(void)
 {
-	if (table_dec)
-		vfree(table_dec);
-	if (table_com)
-		vfree(table_com);
+	vfree(table_dec);
+	vfree(table_com);
 	table_com = NULL;
 	table_dec = NULL;
 }