linux-user/riscv: Use abi type for target_ucontext

We should not use types dependend on host arch for target_ucontext.
This bug is found when run rv32 applications.

Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230811055438.1945-1-zhiwei_liu@linux.alibaba.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
(cherry picked from commit ae7d4d6)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

linux-user/riscv/signal.c

@@ -38,8 +38,8 @@ struct target_sigcontext {
 }; /* cf. riscv-linux:arch/riscv/include/uapi/asm/ptrace.h */
 
 struct target_ucontext {
-    unsigned long uc_flags;
-    struct target_ucontext *uc_link;
+    abi_ulong uc_flags;
+    abi_ptr uc_link;
     target_stack_t uc_stack;
     target_sigset_t uc_sigmask;
     uint8_t   __unused[1024 / 8 - sizeof(target_sigset_t)];