ide: Add tx4938ide driver (v2)

This is the driver for the Toshiba TX4938 SoC EBUS controller ATA mode.
It has custom set_pio_mode and some hacks for big endian.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: ralf@linux-mips.org
Cc: sshtylyov@ru.mvista.com
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/Kconfig

@@ -720,6 +720,11 @@ config BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ
        default "128"
        depends on BLK_DEV_IDE_AU1XXX
 
+config BLK_DEV_IDE_TX4938
+	tristate "TX4938 internal IDE support"
+	depends on SOC_TX4938
+	select IDE_TIMINGS
+
 config BLK_DEV_IDE_TX4939
 	tristate "TX4939 internal IDE support"
 	depends on SOC_TX4939