Fix:
```
riscv-none-elf-ld: sotest.o: ABI is incompatible with that of the selected emulation:
target emulation `elf64-littleriscv' does not match `elf32-littleriscv'
riscv-none-elf-ld: failed to merge target specific data of file sotest.o
```
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>