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/sandbox_spl_defconfig b/configs/sandbox_spl_defconfig
index ca5ac7f..6741cd0 100644
--- a/configs/sandbox_spl_defconfig
+++ b/configs/sandbox_spl_defconfig
@@ -31,7 +31,7 @@
 CONFIG_HANDOFF=y
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_ENV_SUPPORT=y
-CONFIG_SPL_I2C_SUPPORT=y
+CONFIG_SPL_I2C=y
 CONFIG_SPL_RTC_SUPPORT=y
 CONFIG_CMD_CPU=y
 CONFIG_CMD_LICENSE=y