bootmeth: use efi_loader interfaces instead of bootefi command

Now that efi_loader subsystem provides interfaces that are equivalent
with bootefi command, we can replace command invocations with APIs.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index b21a30c..24bfbe5 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -273,7 +273,7 @@
 
 config BOOTM_EFI
 	bool "Support booting UEFI FIT images"
-	depends on CMD_BOOTEFI && CMD_BOOTM && FIT
+	depends on BOOTEFI_BOOTMGR && CMD_BOOTM && FIT
 	default y
 	help
 	  Support booting UEFI FIT images via the bootm command.