Rename SPL_POWER_SUPPORT to SPL_POWER

Rename this option so that CONFIG_IS_ENABLED can be used with it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/configs/imx8mm_evk_defconfig b/configs/imx8mm_evk_defconfig
index a06c6f9..568a628 100644
--- a/configs/imx8mm_evk_defconfig
+++ b/configs/imx8mm_evk_defconfig
@@ -29,7 +29,7 @@
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_SEPARATE_BSS=y
 CONFIG_SPL_I2C_SUPPORT=y
-CONFIG_SPL_POWER_SUPPORT=y
+CONFIG_SPL_POWER=y
 CONFIG_SPL_WATCHDOG_SUPPORT=y
 CONFIG_SYS_PROMPT="u-boot=> "
 # CONFIG_CMD_EXPORTENV is not set