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/am3517_evm_defconfig b/configs/am3517_evm_defconfig
index 504b38c..4ece8d8 100644
--- a/configs/am3517_evm_defconfig
+++ b/configs/am3517_evm_defconfig
@@ -27,7 +27,7 @@
 CONFIG_SPL_NAND_SIMPLE=y
 CONFIG_SPL_NAND_BASE=y
 CONFIG_SPL_OS_BOOT=y
-# CONFIG_SPL_POWER_SUPPORT is not set
+# CONFIG_SPL_POWER is not set
 CONFIG_SYS_PROMPT="AM3517_EVM # "
 # CONFIG_CMD_IMI is not set
 CONFIG_CMD_SPL=y