compile with rv64imafdc

[MarkLai0317]

My risc-v device only support --march=rv64imafdc.
So the compilation of .S file in "/source/device/cpu/op/conv/risc-v/lp64dv" will fail because my device cannot support vector operation.

How to compile with only rv64imafdc support ?

[YJack0000]

I'm facing the same problem, but seems like Tengine can only support rv64gcvxthead becase v(vector) module seem important to the riscv support on this project.