Bump buidlroot version to 2018.02.6

bsp/buildroot/package/libssh2/Config.in

@@ -1,6 +1,6 @@
 config BR2_PACKAGE_LIBSSH2
 	bool "libssh2"
-	select BR2_PACKAGE_OPENSSL if !BR2_PACKAGE_LIBGCRYPT
+	select BR2_PACKAGE_OPENSSL if !(BR2_PACKAGE_MBEDTLS || BR2_PACKAGE_LIBGCRYPT)
 	help
 	  libssh2 is a client-side C library implementing the SSH2
 	  protocol as defined by Internet Drafts: SECSH-TRANS(22),
@@ -8,3 +8,25 @@ config BR2_PACKAGE_LIBSSH2
 	  SECSH-FILEXFER(06)*, SECSH-DHGEX(04), and SECSH-NUMBERS(10)
 
 	  http://www.libssh2.org/
+
+if BR2_PACKAGE_LIBSSH2
+
+choice
+	prompt "Crypto Backend"
+	help
+	  Select crypto library to be used in libssh2.
+
+config BR2_PACKAGE_LIBSSH2_MBEDTLS
+	bool "mbedtls"
+	depends on BR2_PACKAGE_MBEDTLS
+
+config BR2_PACKAGE_LIBSSH2_LIBGCRYPT
+	bool "gcrypt"
+	depends on BR2_PACKAGE_LIBGCRYPT
+
+config BR2_PACKAGE_LIBSSH2_OPENSSL
+	bool "openssl"
+	depends on BR2_PACKAGE_OPENSSL
+
+endchoice
+endif