[PATCH] accel/tcg: Add stub for probe_access()

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

The TCG helpers where added in b92e5a22ec3 in softmmu_template.h.
probe_write() was added in there in 3b4afc9e75a to be moved out
to accel/tcg/cputlb.c in 3b08f0a9254, and was later refactored
as probe_access() in c25c283df0f.
Since it is a TCG specific helper, add a stub to avoid failures
when building without TCG, such:

  target/arm/helper.o: In function `probe_read':
  include/exec/exec-all.h:345: undefined reference to `probe_access'

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
Cc: Richard Henderson <rth@twiddle.net>
Cc: Emilio G. Cota <cota@braap.org>
Cc: Alex Bennée <alex.bennee@linaro.org>
Cc: David Hildenbrand <david@redhat.com>
---
 accel/stubs/tcg-stub.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/accel/stubs/tcg-stub.c b/accel/stubs/tcg-stub.c
index 677191a69c..e4bbf997aa 100644
--- a/accel/stubs/tcg-stub.c
+++ b/accel/stubs/tcg-stub.c
@@ -22,3 +22,10 @@ void tb_flush(CPUState *cpu)
 void tlb_set_dirty(CPUState *cpu, target_ulong vaddr)
 {
 }
+
+void *probe_access(CPUArchState *env, target_ulong addr, int size,
+                   MMUAccessType access_type, int mmu_idx, uintptr_t retaddr)
+{
+     /* Handled by hardware accelerator. */
+     g_assert_not_reached();
+}
-- 
2.21.1