avbtool: Use root=/dev/dm-0 instead of root=0xfd00.
It was pointed out that major/minor numbers could be dynamically
allocated. While this is unlikely, just use /dev/dm-0 which is
guaranteed to always refer to the first mapped device.
Bug: 36444660
Test: All unit tests pass.
Test: Manually tested on UEFI based bootloader.
Change-Id: If591fae1ee657ab6da0ab9b140e45965104da3fd
diff --git a/avbtool b/avbtool
index bb23db2..2dfb259 100755
--- a/avbtool
+++ b/avbtool
@@ -1907,7 +1907,7 @@
c += ' 2' # number of optional args
c += ' restart_on_corruption'
c += ' ignore_zero_blocks'
- c += '" root=0xfd00'
+ c += '" root=/dev/dm-0'
# Now that we have the command-line, generate the descriptor.
desc = AvbKernelCmdlineDescriptor()