efi: fix missing prototype warnings

The cper.c file needs to include an extra header, and efi_zboot_entry
needs an extern declaration to avoid these 'make W=1' warnings:

drivers/firmware/efi/libstub/zboot.c:65:1: error: no previous prototype for 'efi_zboot_entry' [-Werror=missing-prototypes]
drivers/firmware/efi/efi.c:176:16: error: no previous prototype for 'efi_attr_is_visible' [-Werror=missing-prototypes]
drivers/firmware/efi/cper.c:626:6: error: no previous prototype for 'cper_estatus_print' [-Werror=missing-prototypes]
drivers/firmware/efi/cper.c:649:5: error: no previous prototype for 'cper_estatus_check_header' [-Werror=missing-prototypes]
drivers/firmware/efi/cper.c:662:5: error: no previous prototype for 'cper_estatus_check' [-Werror=missing-prototypes]

To make this easier, move the cper specific declarations to
include/linux/cper.h.

Signed-off-by: Arnd Bergmann <[e-mail]>
Acked-by: Rafael J. Wysocki <[e-mail]>
Signed-off-by: Ard Biesheuvel <[e-mail]>

drivers/acpi/apei/apei-internal.h

···
 #ifndef APEI_INTERNAL_H
 #define APEI_INTERNAL_H
 
-#include <linux/cper.h>
 #include <linux/acpi.h>
 
 struct apei_exec_context;
···
 	else
 		return sizeof(*estatus) + estatus->data_length;
 }
-
-void cper_estatus_print(const char *pfx,
-			const struct acpi_hest_generic_status *estatus);
-int cper_estatus_check_header(const struct acpi_hest_generic_status *estatus);
-int cper_estatus_check(const struct acpi_hest_generic_status *estatus);
 
 int apei_osc_setup(void);
 #endif

drivers/acpi/apei/bert.c

···
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
+#include <linux/cper.h>
 #include <linux/io.h>
 
 #include "apei-internal.h"

drivers/firmware/efi/libstub/efistub.h

···
 void efi_remap_image(unsigned long image_base, unsigned alloc_size,
 		     unsigned long code_size);
 
+asmlinkage efi_status_t __efiapi
+efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab);
+
 #endif

include/linux/cper.h

···
 int cper_mem_err_location(struct cper_mem_err_compact *mem, char *msg);
 int cper_dimm_err_location(struct cper_mem_err_compact *mem, char *msg);
 
+struct acpi_hest_generic_status;
+void cper_estatus_print(const char *pfx,
+			const struct acpi_hest_generic_status *estatus);
+int cper_estatus_check_header(const struct acpi_hest_generic_status *estatus);
+int cper_estatus_check(const struct acpi_hest_generic_status *estatus);
+
 #endif

include/linux/efi.h

···
 	return xen_efi_config_table_is_usable(guid, table);
 }
 
+umode_t efi_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n);
+
 #endif /* _LINUX_EFI_H */