i2c: Rename SPL/TPL_I2C_SUPPORT to I2C

Rename these options so that CONFIG_IS_ENABLED can be used with them.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/configs/am335x_sl50_defconfig b/configs/am335x_sl50_defconfig
index 677daa4..1f3b680 100644
--- a/configs/am335x_sl50_defconfig
+++ b/configs/am335x_sl50_defconfig
@@ -23,7 +23,7 @@
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_SPL_ENV_SUPPORT=y
 CONFIG_SPL_FS_EXT4=y
-CONFIG_SPL_I2C_SUPPORT=y
+CONFIG_SPL_I2C=y
 CONFIG_SPL_MTD_SUPPORT=y
 # CONFIG_SPL_NAND_SUPPORT is not set
 CONFIG_SPL_NAND_DRIVERS=y