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/arch/arm/Kconfig b/arch/arm/Kconfig
index 9de97cc..2b5e7a8 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1023,7 +1023,7 @@
 	imply SPL_LIBCOMMON_SUPPORT
 	imply SPL_LIBGENERIC_SUPPORT
 	imply SPL_MMC_SUPPORT if MMC
-	imply SPL_POWER_SUPPORT
+	imply SPL_POWER
 	imply SPL_SERIAL_SUPPORT
 	imply USB_GADGET