package/libopenssl: make use of linux-generic64 for 64-bit archs

It was tested with:

BR2_mips64el=y
BR2_MIPS_NABI64=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y
BR2_TOOLCHAIN_EXTERNAL_URL="http://autobuild.buildroot.org/toolchains/tarballs/br-mips64-n64-full-2019.05.1.tar.bz2"
BR2_TOOLCHAIN_EXTERNAL_GCC_5=y
BR2_TOOLCHAIN_EXTERNAL_HEADERS_5_1=y
BR2_TOOLCHAIN_EXTERNAL_LOCALE=y
BR2_TOOLCHAIN_EXTERNAL_CXX=y
BR2_INIT_NONE=y
BR2_SYSTEM_BIN_SH_NONE=y
BR2_PACKAGE_OPENSSL=y

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/libopenssl/Config.in

@@ -24,6 +24,7 @@ config BR2_PACKAGE_LIBOPENSSL_TARGET_ARCH
 	default "linux-ppc64le"			if BR2_powerpc64le
 	default "linux-x86_64"			if BR2_x86_64
 	# no-asm is needed with generic architectures such as
-	# linux-generic32, see
+	# linux-generic{32,64}, see
 	# https://github.com/openssl/openssl/issues/9839
+	default "linux-generic64 no-asm"	if BR2_ARCH_IS_64
 	default "linux-generic32 no-asm"