Correct SPL uses of FASTBOOT

This converts 3 usages of this option to the non-SPL form, since there is
no SPL_FASTBOOT defined in Kconfig

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-rockchip/board.c b/arch/arm/mach-rockchip/board.c
index 6e05a8f..ebffb6c 100644
--- a/arch/arm/mach-rockchip/board.c
+++ b/arch/arm/mach-rockchip/board.c
@@ -306,7 +306,7 @@
 
 #endif /* CONFIG_USB_GADGET */
 
-#if CONFIG_IS_ENABLED(FASTBOOT)
+#if IS_ENABLED(CONFIG_FASTBOOT)
 int fastboot_set_reboot_flag(enum fastboot_reboot_reason reason)
 {
 	if (reason != FASTBOOT_REBOOT_REASON_BOOTLOADER)
diff --git a/board/ti/am57xx/board.c b/board/ti/am57xx/board.c
index 0e57ee5..9ea507a 100644
--- a/board/ti/am57xx/board.c
+++ b/board/ti/am57xx/board.c
@@ -1172,7 +1172,7 @@
 }
 #endif
 
-#if CONFIG_IS_ENABLED(FASTBOOT) && !CONFIG_IS_ENABLED(ENV_IS_NOWHERE)
+#if IS_ENABLED(CONFIG_FASTBOOT) && !CONFIG_IS_ENABLED(ENV_IS_NOWHERE)
 int fastboot_set_reboot_flag(enum fastboot_reboot_reason reason)
 {
 	if (reason != FASTBOOT_REBOOT_REASON_BOOTLOADER)
diff --git a/board/ti/dra7xx/evm.c b/board/ti/dra7xx/evm.c
index 568c8fb..a8a216d 100644
--- a/board/ti/dra7xx/evm.c
+++ b/board/ti/dra7xx/evm.c
@@ -1049,7 +1049,7 @@
 }
 #endif
 
-#if CONFIG_IS_ENABLED(FASTBOOT) && !CONFIG_IS_ENABLED(ENV_IS_NOWHERE)
+#if IS_ENABLED(CONFIG_FASTBOOT) && !CONFIG_IS_ENABLED(ENV_IS_NOWHERE)
 int fastboot_set_reboot_flag(enum fastboot_reboot_reason reason)
 {
 	if (reason != FASTBOOT_REBOOT_REASON_BOOTLOADER)