ata: mvebu: move mvebu sata driver to drivers/ata directory

Currently mvebu sata driver is in arch/arm/mach_mvebu directory, this
patch moves it to drivers/ata directory with renaming "sata.c" to
"ahci_mvebu.c" which is aligned to Linux.
New ahci driver's kconfig option is added as AHCI_MVEBU which selects
SCSI_AHCI and is based on AHCI.

Signed-off-by: Ken Ma <make@marvell.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/MAINTAINERS b/MAINTAINERS
index 3209dcd..0289d9d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -135,6 +135,7 @@
 T:	git git://git.denx.de/u-boot-marvell.git
 F:	arch/arm/mach-kirkwood/
 F:	arch/arm/mach-mvebu/
+F:	drivers/ata/ahci_mvebu.c
 
 ARM MARVELL PXA
 M:	Marek Vasut <marex@denx.de>