fw_cfg: remove useless declarations from typedefs.h

Only FWCfgState is used as part of APIs such as acpi_ghes_add_fw_cfg.
Everything else need not be in typedefs.h.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/hw/nvram/fw_cfg.h

@@ -59,6 +59,8 @@ typedef struct fw_cfg_dma_access FWCfgDmaAccess;
 typedef void (*FWCfgCallback)(void *opaque);
 typedef void (*FWCfgWriteCallback)(void *opaque, off_t start, size_t len);
 
+typedef struct FWCfgEntry FWCfgEntry;
+
 struct FWCfgState {
     /*< private >*/
     SysBusDevice parent_obj;