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/P1020RDB-PC_SPIFLASH_defconfig b/configs/P1020RDB-PC_SPIFLASH_defconfig
index 13e63c7..d7a22f3 100644
--- a/configs/P1020RDB-PC_SPIFLASH_defconfig
+++ b/configs/P1020RDB-PC_SPIFLASH_defconfig
@@ -5,6 +5,7 @@
 CONFIG_SPL_SPI_FLASH_SUPPORT=y
 CONFIG_SPL_SPI_SUPPORT=y
 CONFIG_MPC85xx=y
+# CONFIG_CMD_ERRATA is not set
 CONFIG_TARGET_P1020RDB_PC=y
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y