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/P1020MBG-PC_36BIT_SDCARD_defconfig b/configs/P1020MBG-PC_36BIT_SDCARD_defconfig
index e50bbb7..698e42a 100644
--- a/configs/P1020MBG-PC_36BIT_SDCARD_defconfig
+++ b/configs/P1020MBG-PC_36BIT_SDCARD_defconfig
@@ -4,6 +4,7 @@
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_SPL_SERIAL_SUPPORT=y
 CONFIG_MPC85xx=y
+# CONFIG_CMD_ERRATA is not set
 CONFIG_TARGET_P1020MBG=y
 CONFIG_PHYS_64BIT=y
 CONFIG_FIT=y