hw/hyperv: Include missing headers

hw/hyperv: Include missing headers

Include missing headers in order to avoid when refactoring
unrelated headers:

  hw/hyperv/hyperv.c:33:18: error: field ‘msg_page_mr’ has incomplete type
    33 |     MemoryRegion msg_page_mr;
       |                  ^~~~~~~~~~~
  hw/hyperv/hyperv.c: In function ‘synic_update’:
  hw/hyperv/hyperv.c:64:13: error: implicit declaration of function ‘memory_region_del_subregion’ [-Werror=implicit-function-declaration]
    64 |             memory_region_del_subregion(get_system_memory(),
       |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~
  hw/hyperv/hyperv.c: In function ‘hyperv_hcall_signal_event’:
  hw/hyperv/hyperv.c:683:17: error: implicit declaration of function ‘ldq_phys’; did you mean ‘ldub_phys’? [-Werror=implicit-function-declaration]
   683 |         param = ldq_phys(&address_space_memory, addr);
       |                 ^~~~~~~~
       |                 ldub_phys
  hw/hyperv/hyperv.c:683:17: error: nested extern declaration of ‘ldq_phys’ [-Werror=nested-externs]
  hw/hyperv/hyperv.c: In function ‘hyperv_hcall_retreive_dbg_data’:
  hw/hyperv/hyperv.c:792:24: error: ‘TARGET_PAGE_SIZE’ undeclared (first use in this function); did you mean ‘TARGET_PAGE_BITS’?
   792 |     msg.u.recv.count = TARGET_PAGE_SIZE - sizeof(*debug_data_out);
       |                        ^~~~~~~~~~~~~~~~
       |                        TARGET_PAGE_BITS
  hw/hyperv/hyperv.c: In function ‘hyperv_syndbg_send’:
  hw/hyperv/hyperv.c:885:16: error: ‘HV_SYNDBG_STATUS_INVALID’ undeclared (first use in this function)
   885 |         return HV_SYNDBG_STATUS_INVALID;
       |                ^~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>