efi: Fix efi_loaded_image_t::unload type

efi: Fix efi_loaded_image_t::unload type

The ::unload field is a function pointer, so it should be u32 for 32-bit,
u64 for 64-bit. Add a prototype for it in the native efi_loaded_image_t
type. Also change type of parent_handle and device_handle from void * to
efi_handle_t for documentation purposes.

The unload method is not used, so no functional change.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191206165542.31469-6-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>