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/configs/sbc8349_defconfig b/configs/sbc8349_defconfig
index 1141b79..f7c3de8 100644
--- a/configs/sbc8349_defconfig
+++ b/configs/sbc8349_defconfig
@@ -2,6 +2,7 @@
 CONFIG_SYS_TEXT_BASE=0xFF800000
 CONFIG_SYS_CLK_FREQ=66000000
 CONFIG_MPC83xx=y
+CONFIG_HIGH_BATS=y
 CONFIG_TARGET_SBC8349=y
 CONFIG_DDR_MC_CLOCK_MODE_1_1=y
 CONFIG_SYSTEM_PLL_FACTOR_4_1=y