bootm: don't call booti_setup for EFI images

On the arm64 architecture booti_setup() is called for EFI FIT images.
This function call fails because EFI images typically do not have a
kernel signature.

Check that the operating system property "os" of the image is "linux"
before invoking booti_setup().

Fixes: 487b5fa6deb1 ("bootm: Handle kernel_noload on arm64")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/bootm.c b/boot/bootm.c
index 4144ff3..75f0b4a 100644
--- a/boot/bootm.c
+++ b/boot/bootm.c
@@ -240,7 +240,8 @@
 
 	if (images.os.type == IH_TYPE_KERNEL_NOLOAD) {
 		if (IS_ENABLED(CONFIG_CMD_BOOTI) &&
-		    images.os.arch == IH_ARCH_ARM64) {
+		    images.os.arch == IH_ARCH_ARM64 &&
+		    images.os.os == IH_OS_LINUX) {
 			ulong image_addr;
 			ulong image_size;