efi_loader: installation of EFI_RNG_PROTOCOL

Having an EFI_RNG_PROTOCOL without a backing RNG device leads to failure
to boot Linux 5.8.

Only install the EFI_RNG_PROTOCOL if we have a RNG device.

Reported-by: Scott K Logan <logans@cottsay.net>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

lib/efi_loader/efi_root_node.c

@@ -80,10 +80,6 @@ efi_status_t efi_root_node_register(void)
 			 /* HII configuration routing protocol */
 			 &efi_guid_hii_config_routing_protocol,
 			 (void *)&efi_hii_config_routing,
-#endif
-#if CONFIG_IS_ENABLED(EFI_RNG_PROTOCOL)
-			 &efi_guid_rng_protocol,
-			 (void *)&efi_rng_protocol,
 #endif
 			 NULL));
 	efi_root->type = EFI_OBJECT_TYPE_U_BOOT_FIRMWARE;