package/freeradius-server: requires MD4 in openssl

Enable MD4 in openssl to avoid the following build failure raised since
the addition of the package in commit
736c4c1655d93652a9a7e79235bbe726b3d46176:

In file included from src/lib/md4.c:16:
src/lib/md4.c: In function 'fr_md4_calc':
src/freeradius-devel/md4.h:76:33: error: unknown type name 'MD4_CTX'; did you mean 'FR_MD4_CTX'?
   76 | #  define FR_MD4_CTX            MD4_CTX
      |                                 ^~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/a8aa12a8129056391f975820ea3d1d62241ac051

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/freeradius-server/Config.in

@@ -4,6 +4,7 @@ config BR2_PACKAGE_FREERADIUS_SERVER
 	depends on !BR2_STATIC_LIBS # libtalloc
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_TOOLCHAIN_USES_GLIBC
+	select BR2_PACKAGE_LIBOPENSSL_ENABLE_MD4 if BR2_PACKAGE_LIBOPENSSL
 	select BR2_PACKAGE_LIBTALLOC
 	help
 	  FreeRADIUS is an open source server which implements