Enable RISCV AOT support, the supported ABIs are LP64 and LP64D for riscv64, ILP32 and ILP32D for riscv32.
For wamrc:
use --target=riscv64/riscv32 to specify the target arch of output AOT file,
use --target-abi=lp64d/lp64/ilp32d/ilp32 to specify the target ABI,
if --target-abi isn't specified, by default lp64d is used for riscv64, and ilp32d is used for riscv32.
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
Co-authored-by: wenyongh <wenyong.huang@intel.com>
