[ALSA] Fix control/status mmap with shared PCM substream

The flag to avoid 32bit-incompatible mmap for control/status records
should be outside the pcm substream instance since a substream can be
shared among multiple opens.  Now it's flagged in pcm_file list that
is directly assigned to file->private_data.
Also, removed snd_pcm_add_file() and remove_file() functions and
substream.files field that are not really used in the code.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index f84d849..60d40b3 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -190,7 +190,7 @@
 
 struct snd_pcm_file {
 	struct snd_pcm_substream *substream;
-	struct snd_pcm_file *next;
+	int no_compat_mmap;
 };
 
 struct snd_pcm_hw_rule;
@@ -384,7 +384,6 @@
 	struct snd_info_entry *proc_prealloc_entry;
 #endif
 	/* misc flags */
-	unsigned int no_mmap_ctrl: 1;
 	unsigned int hw_opened: 1;
 };
 
@@ -402,7 +401,6 @@
 	/* -- OSS things -- */
 	struct snd_pcm_oss_stream oss;
 #endif
-	struct snd_pcm_file *files;
 #ifdef CONFIG_SND_VERBOSE_PROCFS
 	struct snd_info_entry *proc_root;
 	struct snd_info_entry *proc_info_entry;