tcg: Include missing 'cpu.h' in translate-all.c

tb_check_watchpoint() calls cpu_get_tb_cpu_state(),
which is declared in each "cpu.h" header. It is indirectly
included via "tcg/insn-start-words.h". Since we want to
rework "tcg/insn-start-words.h", removing "cpu.h" in the
next commit, add the missing header now, otherwise we'd
get:

  accel/tcg/translate-all.c:598:9: error: call to undeclared function 'cpu_get_tb_cpu_state' [-Wimplicit-function-declaration]
  598 |         cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
      |         ^

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

accel/tcg/translate-all.c

@@ -69,6 +69,7 @@
 #include "internal-target.h"
 #include "tcg/perf.h"
 #include "tcg/insn-start-words.h"
+#include "cpu.h"
 
 TBContext tb_ctx;