Add riscv64 asm_arch to BSD-riscv64 target
Add riscv64 asm_arch to BSD-riscv64 target

Following cb2764f2a8 Add riscv64 asm_arch to linux64-riscv64 target
Current ASM does not have Linux specific thing thus this is
suitable for BSD

Reviewed-by: Todd Short <0267f0ecbdb3e99cdfd94eb139bf30919fa04d2f@me.com>
Reviewed-by: Paul Dale <ddec78389666b4f7c9b4d110380c848489a3e4aa@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18309)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl