Convert CONFIG_CMD_ERRATA to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_ERRATA

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/sbc8548_defconfig b/configs/sbc8548_defconfig
index 3ffbe5b..234804d 100644
--- a/configs/sbc8548_defconfig
+++ b/configs/sbc8548_defconfig
@@ -1,5 +1,6 @@
 CONFIG_PPC=y
 CONFIG_MPC85xx=y
+# CONFIG_CMD_ERRATA is not set
 CONFIG_TARGET_SBC8548=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_STDOUT_VIA_ALIAS=y