ata: ahci_sunxi: Disable DIPM

DIPM is unsupported or broken on sunxi. Trying to enable the power
management policy med_power_with_dipm on an Allwinner A20 SoC based board
leads to immediate I/O errors and the attached SATA disk disappears from
the /dev filesystem. A reset (power cycle) is required to make the SATA
controller or disk work again. The A10 and A20 SoC data sheets and manuals
don't mention DIPM at all [1], so it's fair to assume that it's simply not
supported. But even if it was, it should be considered broken and best be
disabled in the ahci_sunxi driver.

[1] https://github.com/allwinner-zh/documents/tree/master/

Fixes: c5754b5220f0 ("ARM: sunxi: Add support for Allwinner SUNXi SoCs sata to ahci_platform")
Cc: [e-mail]
Signed-off-by: Timo Sigurdsson <[e-mail]>
Tested-by: Timo Sigurdsson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/ata/ahci_sunxi.c

···
 }
 
 static const struct ata_port_info ahci_sunxi_port_info = {
-	.flags		= AHCI_FLAG_COMMON | ATA_FLAG_NCQ,
+	.flags		= AHCI_FLAG_COMMON | ATA_FLAG_NCQ | ATA_FLAG_NO_DIPM,
 	.pio_mask	= ATA_PIO4,
 	.udma_mask	= ATA_UDMA6,
 	.port_ops	= &ahci_platform_ops,