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/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index 3d44b45..8f0842c 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -111,6 +111,14 @@
 }
 EXPORT_SYMBOL_GPL(ide_io_buffers);
 
+void ide_init_pc(struct ide_atapi_pc *pc)
+{
+	memset(pc, 0, sizeof(*pc));
+	pc->buf = pc->pc_buf;
+	pc->buf_size = IDE_PC_BUFFER_SIZE;
+}
+EXPORT_SYMBOL_GPL(ide_init_pc);
+
 /* TODO: unify the code thus making some arguments go away */
 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,