[ALSA] Remove snd_runtime_check() macro

Remove snd_runtime_check() macro.
This macro worsens the readability of codes.  They should be either
normal if() or removable asserts.

Also, the assert displays stack-dump, instead of only the last caller
pointer.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 1be470e..184e74b 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -273,7 +273,8 @@
 	snd_pcm_info_t *info;
 	int err;
 
-	snd_runtime_check(substream, return);
+	if (! substream)
+		return;
 
 	info = kmalloc(sizeof(*info), GFP_KERNEL);
 	if (! info) {