sparc32, leon: Stop adding vendor and device id to prom ambapp path components

These extra fields before the @ are not handled in of_node_name_eq,
making commit b3e46d1a break node name
comparisons for ambapp path components, thereby making LEON systems
unable to boot.

As there is no need for the tacked on vendor and device ID fields in the
path component, resolve this situation by removing them.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>