utils: refine log when booting windows UEFI from DOS partition

Refine 97647c32aa utils: add enforce_gpt argument to get_efi_partition()
to provide more explicit error when trying to boot Windows UEFI from DOS
partition.

src/utils/disk.py

@@ -61,7 +61,7 @@ def get_efi_partition(disknum, enforce_gpt):
     cxt = fdisk.Context(f'/dev/{disk}')
 
     if enforce_gpt and cxt.label == fdisk.FDISK_DISKLABEL_DOS:
-        raise RuntimeError(f'Disk has DOS partition scheme, cannot find ESP at /dev/{disk}')
+        raise RuntimeError(f'Windows EFI System requires GPT partition scheme, but /dev/{disk} has DOS partition scheme')
 
     for pa in cxt.partitions:
         logging.info(f'Checking partition "{pa.type.name}"...')