efi_loader: typedef struct efi_object *efi_handle_t

All our handles point to a struct efi_object. So let's define the
efi_handle_t accordingly. This helps us to discover coding errors much
more easily. This becomes evident by the corrections to the usage of
handles in this patch.

Rename variable image_handle to image_obj where applicable.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
6 files changed