ata: Migrate CONFIG_SCSI_AHCI to Kconfig

And use 'imply' liberally.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/arch/x86/cpu/qemu/Kconfig b/arch/x86/cpu/qemu/Kconfig
index 81444f3..0a801aa 100644
--- a/arch/x86/cpu/qemu/Kconfig
+++ b/arch/x86/cpu/qemu/Kconfig
@@ -9,6 +9,7 @@
 	select ARCH_EARLY_INIT_R
 	imply AHCI_PCI
 	imply E1000
+	imply SCSI_AHCI
 	imply SYS_NS16550
 	imply USB
 	imply USB_EHCI_HCD