accel/hvf: Include missing 'hw/core/cpu.h' header

accel/hvf: Include missing 'hw/core/cpu.h' header

Since commit d5bd8d8267e ("hvf: only update sysreg from owning
thread") hvf-all.c accesses the run_on_cpu_data type and calls
run_on_cpu(), both defined in the "hw/core/cpu.h" header.
Fortunately, it is indirectly included via:

  "system/hvf.h"
    -> "target/arm/cpu.h"
         -> "target/arm/cpu-qom.h"
              -> "hw/core/cpu.h"

"system/hvf.h" however doesn't need "target/arm/cpu.h" and we
want to remove it there. In order to do that we first need to
include it in hvf-all.c, otherwise we get:

  ../accel/hvf/hvf-all.c:61:54: error: unknown type name 'run_on_cpu_data'
   61 | static void do_hvf_update_guest_debug(CPUState *cpu, run_on_cpu_data arg)
      |                                                      ^
  ../accel/hvf/hvf-all.c:68:5: error: call to undeclared function 'run_on_cpu'
   68 |     run_on_cpu(cpu, do_hvf_update_guest_debug, RUN_ON_CPU_NULL);
      |     ^
  ../accel/hvf/hvf-all.c:68:48: error: use of undeclared identifier 'RUN_ON_CPU_NULL'
   68 |     run_on_cpu(cpu, do_hvf_update_guest_debug, RUN_ON_CPU_NULL);
      |                                                ^

Cc: Mads Ynddal <m.ynddal@samsung.com>
Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Mads Ynddal <mads@ynddal.dk>
Message-Id: <20250507204401.45379-1-philmd@linaro.org>