hw/core/loader: Remove declarations of option_rom_has_mr/rom_file_has_mr

These globals were moved to MachineClass by commit 71ae9e94d9 ("pc: Move
option_rom_has_mr/rom_file_has_mr globals to MachineClass"). Finish cleanup.

Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

include/hw/loader.h

@@ -251,9 +251,6 @@ void pstrcpy_targphys(const char *name,
                       hwaddr dest, int buf_size,
                       const char *source);
 
-extern bool option_rom_has_mr;
-extern bool rom_file_has_mr;
-
 ssize_t rom_add_file(const char *file, const char *fw_dir,
                      hwaddr addr, int32_t bootindex,
                      bool option_rom, MemoryRegion *mr, AddressSpace *as);