Fix fdt_find_node(). We should make sure we match the full name when

Fix fdt_find_node().  We should make sure we match the full name when
matching path components (but we do allow matches with the @unit bit).

This fixes a problem on the Milk-V Pioneer where /soc/serial@123456
accidentally match a /socket0-clocks node and we would fail to find the
serial console.

ok miod@