openssl: build the riscv64 assembly

The linux-riscv64-openwrt target inherits linux-generic64, which sets no
asm_arch, so OpenSSL builds only its C code on riscv64. Inherit
linux64-riscv64 instead. That adds the riscv64 assembly for AES, GHASH,
ChaCha20 and SHA-2, which uses the Zb*, Zk* and vector crypto extensions
only when the CPU reports them at runtime.

libcrypto.so.3 grows by 24 KiB, and is 2.3 KiB smaller after xz.

Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Julius Bairaktaris <julius@bairaktaris.de>
Link: https://github.com/openwrt/openwrt/pull/25581
Signed-off-by: Robert Marko <robimarko@gmail.com>

package/libs/openssl/patches/110-openwrt_targets.patch

@@ -9,7 +9,7 @@ Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>
 
 --- /dev/null
 +++ b/Configurations/25-openwrt.conf
-@@ -0,0 +1,52 @@
+@@ -0,0 +1,51 @@
 +## Openwrt "CONFIG_ARCH" matching targets.
 +
 +# The targets need to end in '-openwrt' for the AFALG patch to work
@@ -50,8 +50,7 @@ Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>
 +        perlasm_scheme  => "linux64v2",
 +    },
 +    "linux-riscv64-openwrt" => {
-+        inherit_from    => [ "linux-generic64" ],
-+        perlasm_scheme   => "linux64",
++        inherit_from    => [ "linux64-riscv64" ],
 +    },
 +    "linux-x86_64-openwrt" => {
 +        inherit_from    => [ "linux-x86_64" ],