efi_loader: remove efi_delete_handle on loadfile2

Loadfile2 code is installing two protocols on it's own handle
and uses efi_delete_handle() to clean it up on failure(s). However
commit 05c4c9e21ae6 ("efi_loader: define internal implementations of
install/uninstallmultiple") prepares the ground for us to clean up
efi_delete_handle() used in favor of Install/UninstallMultipleProtocol.

While at it clean up the non needed void casts to (void *) on the
protolcol installation.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 1bac3f4..0c6c95b 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -570,7 +570,7 @@
 /* Called by bootefi to make the watchdog available */
 efi_status_t efi_watchdog_register(void);
 efi_status_t efi_initrd_register(void);
-void efi_initrd_deregister(void);
+efi_status_t efi_initrd_deregister(void);
 /* Called by bootefi to make SMBIOS tables available */
 /**
  * efi_acpi_register() - write out ACPI tables