scripts/Makefile.lib: fixes: Embed capsule public key in platform's dtb

The call to cmd_capsule_esl_gen was made directly rather than using the
"cmd,xxx" syntax.

Fixes: c7d4dfcd ("scripts/Makefile.lib: Embed capsule public key in
platform's dtb")

Signed-off-by: Jonathan Humphreys <j-humphreys@ti.com>
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 3e68d5a..d3c95f3 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -351,7 +351,7 @@
 	$(error "CONFIG_EFI_CAPSULE_ESL_FILE is empty, EFI capsule authentication \
 	public key must be specified when CONFIG_EFI_CAPSULE_AUTHENTICATE is enabled")
 else
-	$(call cmd_capsule_esl_gen)
+	$(call cmd,capsule_esl_gen)
 endif
 
 capsule_esl_input_file=$(srctree)/lib/efi_loader/capsule_esl.dtsi.in