ALSA: Remove superfluous header inclusions in memalloc.c

After cutting off the proc and page reservation codes, we don't need
many headers any longer.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/memalloc.c

@@ -22,17 +22,13 @@
  */
 
 #include <linux/module.h>
-#include <linux/proc_fs.h>
 #include <linux/init.h>
-#include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
-#include <linux/seq_file.h>
 #include <asm/uaccess.h>
 #include <linux/dma-mapping.h>
 #include <linux/genalloc.h>
 #include <linux/moduleparam.h>
-#include <linux/mutex.h>
 #include <sound/memalloc.h>