linux-user/hppa: Fix struct target_sigcontext layout

Use abi_ullong not uint64_t so that the alignment of the field
and therefore the layout of the struct is correct.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/hppa/signal.c

@@ -25,7 +25,7 @@
 struct target_sigcontext {
     abi_ulong sc_flags;
     abi_ulong sc_gr[32];
-    uint64_t sc_fr[32];
+    abi_ullong sc_fr[32];
     abi_ulong sc_iasq[2];
     abi_ulong sc_iaoq[2];
     abi_ulong sc_sar;