ata: Migrate CONFIG_FSL_SATA to Kconfig

Use 'imply' here liberally to avoid the combinatorial explosion of
defconfig changes in the PowerPC boards.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/arch/powerpc/cpu/mpc83xx/Kconfig b/arch/powerpc/cpu/mpc83xx/Kconfig
index a377973..05d29d2 100644
--- a/arch/powerpc/cpu/mpc83xx/Kconfig
+++ b/arch/powerpc/cpu/mpc83xx/Kconfig
@@ -55,6 +55,7 @@
 	bool "Support MPC837XEMDS"
 	select BOARD_EARLY_INIT_F
 	imply CMD_SATA
+	imply FSL_SATA
 
 config TARGET_MPC837XERDB
 	bool "Support MPC837XERDB"