ata: sata_sil: Add DM support for Silicon sata driver

Add DM support for Silicon(SIL3131 / SIL3132 / SIL3124) sata driver as
few of the PowerPC platforms such as P series based boards need to
use SATA_SIL with DM,

Also fix below warning while PowerPC P series boards compilation,

===================== WARNING ======================"
This board does use CONFIG_LIBATA but has CONFIG_AHCI not"
enabled. Please update the storage controller driver to use"
CONFIG_AHCI before the v2019.07 release."
Failure to update by the deadline may result in board removal."
See doc/driver-model/MIGRATION.txt for more info."
===================================================="
Signed-off-by: NPeng Ma <peng.ma@nxp.com>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>

drivers/ata/Kconfig

@@ -110,6 +110,7 @@ config SATA_MV
 config SATA_SIL
 	bool "Enable Silicon Image SIL3131 / SIL3132 / SIL3124 SATA driver support"
 	select LIBATA
+	select AHCI if BLK
 	help
 	  Enable this driver to support the SIL3131, SIL3132 and SIL3124
 	  SATA controllers.

drivers/ata/sata_sil.h

 /* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright (C) 2011 Freescale Semiconductor, Inc.
+ * Copyright 2019 NXP
  * Author: Tang Yuantian <b29983@freescale.com>
  */
 
@@ -24,6 +25,7 @@ struct sil_sata {
 	int		wcache;
 	int		flush;
 	int		flush_ext;
+	int		id;
 };
 
 /* sata info for each controller */
@@ -210,4 +212,12 @@ enum {
 	CMD_ERR		= 0x21,
 };
 
+#if CONFIG_IS_ENABLED(BLK)
+#define ATA_MAX_PORTS		32
+struct sil_sata_priv {
+	int		port_num;
+	struct sil_sata	*sil_sata_desc[ATA_MAX_PORTS];
+};
+#endif
+
 #endif