use `BORINGSS_USE_ASM` in lsquic.nimble

[vladopajic]

theoretically , assuming performance is not required, you should be able to avoid assembly by seting https://github.com/vacp2p/nim-lsquic/blob/main/boringssl.nim#L31 -d:BORINGSS_USE_ASM=false, but that variable should be also checked for in https://github.com/vacp2p/nim-lsquic/blob/main/lsquic.nimble#L23-L46