ide: add ide_init_pc() helper

* Add IDE_PC_BUFFER_SIZE define.

* Add ide_init_pc() and convert ide-{floppy,tape}.c to use it
  instead of ide*_init_pc().

* Remove no longer used IDE*_PC_BUFFER_SIZE and ide*_init_pc().

There should be no functional changes caused by this patch.

Acked-by: Borislav Petkov <petkovbb@gmail.com>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 03dc215..bba2f73 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -724,6 +724,12 @@
 	PC_FLAG_TIMEDOUT		= (1 << 7),
 };
 
+/*
+ * With each packet command, we allocate a buffer of IDE_PC_BUFFER_SIZE bytes.
+ * This is used for several packet commands (not for READ/WRITE commands).
+ */
+#define IDE_PC_BUFFER_SIZE	256
+
 struct ide_atapi_pc {
 	/* actual packet bytes */
 	u8 c[12];
@@ -753,7 +759,7 @@
 	 * those are more or less driver-specific and some of them are subject
 	 * to change/removal later.
 	 */
-	u8 pc_buf[256];
+	u8 pc_buf[IDE_PC_BUFFER_SIZE];
 
 	/* idetape only */
 	struct idetape_bh *bh;
@@ -1113,6 +1119,8 @@
 
 int ide_check_atapi_device(ide_drive_t *, const char *);
 
+void ide_init_pc(struct ide_atapi_pc *);
+
 ide_startstop_t ide_pc_intr(ide_drive_t *drive, struct ide_atapi_pc *pc,
 	ide_handler_t *handler, unsigned int timeout, ide_expiry_t *expiry,
 	void (*update_buffers)(ide_drive_t *, struct ide_atapi_pc *),