bsd-user/arm/signal.c: arm get_ucontext_sigreturn

Update ucontext to implement sigreturn.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

bsd-user/arm/signal.c

@@ -185,3 +185,12 @@ abi_long set_mcontext(CPUARMState *env, target_mcontext_t *mcp, int srflag)
 
     return err;
 }
+
+/* Compare to arm/arm/machdep.c sys_sigreturn() */
+abi_long get_ucontext_sigreturn(CPUARMState *env, abi_ulong target_sf,
+                                abi_ulong *target_uc)
+{
+    *target_uc = target_sf;
+
+    return 0;
+}