[lwp/riscv]进入libc前初始化用户态sp (#8997)

components/lwp/arch/risc-v/rv64/lwp_gcc.S

@@ -40,7 +40,7 @@ arch_start_umode:
     csrs sstatus, t0
 
     csrw sepc, a1
-    mv a3, a2
+    mv sp, a2
     sret//enter user mode
 
 /*