powerpc: Migrate HIGH_BATS to Kconfig

Migrate the CONFIG_HIGH_BATS variable to Kconfig.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 0b1629b..c2c577f 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -39,6 +39,12 @@
 
 endchoice
 
+config HIGH_BATS
+	bool "Enable high BAT registers"
+	help
+	  Enable BATs (block address translation registers) 4-7 on machines
+	  that support them.
+
 source "arch/powerpc/cpu/mpc83xx/Kconfig"
 source "arch/powerpc/cpu/mpc85xx/Kconfig"
 source "arch/powerpc/cpu/mpc86xx/Kconfig"