efi_loader: Kconfig: Select IMAGE_SIGN_INFO when capsule authentication is enabled

Enable building of the crypto helper functions used during capsule
authentication by selecting IMAGE_SIGN_INFO.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index e44f004..0b99d7c 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -173,6 +173,7 @@
 	select X509_CERTIFICATE_PARSER
 	select PKCS7_MESSAGE_PARSER
 	select PKCS7_VERIFY
+	select IMAGE_SIGN_INFO
 	default n
 	help
 	  Select this option if you want to enable capsule