i.MX7ULP: Fix wrong i2c configuration name

Wrong I2c driver configuration name is used in codes, so I2c driver is
not built. Correct it.

Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/configs/mx7ulp_evk_defconfig b/configs/mx7ulp_evk_defconfig
index dc6cc2b..b92e0fa 100644
--- a/configs/mx7ulp_evk_defconfig
+++ b/configs/mx7ulp_evk_defconfig
@@ -21,6 +21,7 @@
 CONFIG_IMX_RGPIO2P=y
 # CONFIG_MXC_GPIO is not set
 CONFIG_DM_I2C=y
+CONFIG_SYS_I2C_IMX_LPI2C=y
 CONFIG_DM_MMC=y
 CONFIG_SUPPORT_EMMC_BOOT=y
 CONFIG_FSL_USDHC=y