Ah I was looking on my phone. Needed to scroll horizontally.
So this is the code for chacha20 on openssl: https://github.com/openssl/openssl/blob/OpenSSL_1_1_0-stable/crypto/chacha/chacha_enc.c
and this is for libressl: https://github.com/libressl-portable/openbsd/blob/master/src/lib/libcrypto/chacha/chacha-merged.c
It's based on the same code but still quite different.
In particular, look at this: https://github.com/openssl/openssl/tree/OpenSSL_1_1_0-stable/crypto/chacha/asm
Those are ASM optimized versions for only a few platforms which LibreSSL does not have. Meaning you're comparing the OpenSSL C code to the LibreSSL C code.
Once OpenSSL gets ASM for MIPS, it should be faster.