treewide: use architecture-specific UEFI boot path

The default UEFI boot path depends on the architecture. This change is
needed for aarch64 support.

Change-Id: I69916ac5063e963b67ecdcdd814b0678c61da9fb
Reviewed-on: https://review.monogon.dev/c/monogon/+/4195
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/osbase/build/mkimage/main.go b/osbase/build/mkimage/main.go
index bef7517..3e8d740 100644
--- a/osbase/build/mkimage/main.go
+++ b/osbase/build/mkimage/main.go
@@ -42,6 +42,7 @@
 	flag.StringVar(&biosBootCodePayload, "bios_bootcode", "", "Optional path to the BIOS bootcode which gets placed at the start of the first block of the image. Limited to 440 bytes, padding is not required. It is only used by legacy BIOS boot.")
 	flag.StringVar(&nodeParams, "node_parameters", "", "Path to Node Parameters to be written to the ESP (default: don't write Node Parameters)")
 	flag.StringVar(&outputPath, "out", "", "Path to the resulting disk image or block device")
+	flag.StringVar(&cfg.Architecture, "architecture", "", "CPU architecture")
 	flag.Int64Var(&cfg.PartitionSize.Data, "data_partition_size", 2048, "Override the data partition size (default 2048 MiB). Used only when generating image files.")
 	flag.Int64Var(&cfg.PartitionSize.ESP, "esp_partition_size", 128, "Override the ESP partition size (default: 128MiB)")
 	flag.Int64Var(&cfg.PartitionSize.System, "system_partition_size", 1024, "Override the System partition size (default: 1024MiB)")