Convert CONFIG_I2C_SET_DEFAULT_BUS_NUM et al to Kconfig

This converts the following to Kconfig:
   CONFIG_I2C_SET_DEFAULT_BUS_NUM
   CONFIG_I2C_DEFAULT_BUS_NUMBER

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/MPC8548CDS_legacy_defconfig b/configs/MPC8548CDS_legacy_defconfig
index 26f8ab9..a7138ac 100644
--- a/configs/MPC8548CDS_legacy_defconfig
+++ b/configs/MPC8548CDS_legacy_defconfig
@@ -26,6 +26,7 @@
 CONFIG_ENV_ADDR=0xFFF60000
 CONFIG_DM=y
 CONFIG_DM_I2C=y
+CONFIG_I2C_SET_DEFAULT_BUS_NUM=y
 CONFIG_SYS_I2C_FSL=y
 CONFIG_SYS_I2C_EEPROM_ADDR=0x57
 # CONFIG_MMC is not set