package/casync-nano: enable OpenSSL ChaCha20 support

When building against OpenSSL, ensure the ChaCha20 algorithm is enabled,
which is needed by this package.

Fixes: https://autobuild.buildroot.org/results/3cb/3cb58229dfb47e79c50b4b52ca57b3f56a945ed7

Signed-off-by: Florian Larysch <fl@n621.de>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/casync-nano/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_CASYNC_NANO
 	bool "casync-nano"
 	select BR2_PACKAGE_OPENSSL
+	select BR2_PACKAGE_LIBOPENSSL_ENABLE_CHACHA if BR2_PACKAGE_LIBOPENSSL
 	select BR2_PACKAGE_ZSTD
 	select BR2_PACKAGE_LIBCURL
 	help